Electronic component

ABSTRACT

A electronic component includes a connection electrode on a wiring layer. An electrically conductive layer is connected to the wiring layer via the connection electrode. A protective film covers a cover portion and the electrically conductive layer. A solder bump is electrically connected to the electrically conductive layer via an opening. An alloy layer is between the solder bump and the electrically conductive layer in a thickness direction to join the solder bump to the electrically conductive layer and differs in composition and/or elements from the solder bump. The connection electrode does not overlap the solder bump. The surface of the electrically conductive layer that is located on a protective film side is in contact with the protective film between the alloy layer and an edge of the electrically conductive layer that is located on a connection electrode side.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of priority to Japanese PatentApplication No. 2017-234597 filed on Dec. 6, 2017 and is a ContinuationApplication of PCT Application No. PCT/JP2018/043346 filed on Nov. 26,2018. The entire contents of each application are hereby incorporatedherein by reference.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates generally to electronic components and,more particularly, to an electronic component including solder bumps.

2. Description of the Related Art

One known conventional electronic component is a semiconductor deviceincluding solder bump electrodes (see, for example, Japanese UnexaminedPatent Application Publication No. 2008-016514).

The semiconductor device described in Japanese Unexamined PatentApplication Publication No. 2008-016514 includes a semiconductorelement, bonding pad portions, a passivation film, first openings, a UBM(Under Bump Metal), solder bump electrodes, and a resin film. Thesemiconductor element is, for example, a CMOS (Complementary Metal OxideSemiconductor) device formed on a principal surface of a semiconductorsubstrate. The passivation film covers the bonding pad portions. Eachfirst opening is formed in the passivation film and allows the uppersurface of a corresponding bonding pad portion to be exposed. The UBM isconnected to the bonding pad portion via the first opening. The UBM is alayered film including a first metal film and a second metal film. Eachsolder bump electrode is connected to the upper and side surfaces of thesecond metal film.

In a semiconductor device production method described in JapaneseUnexamined Patent Application Publication No. 2008-016514, a metal seedlayer is formed before the resin film and the solder bump electrodes areformed. The metal seed layer is formed selectively on the upper and sidesurfaces of the second metal layer forming the upper layer of the UBM.During reflow processing performed in the course of forming the solderbump electrodes, a solder pattern (e.g., a solder paste used for aprinting method, a solder layer used for a plating method, or solderballs used for a ball method) reacts with the metal seed layer formed onthe upper surface of the second metal film and also reacts with themetal seed layer formed on the side surfaces of the second metal filmthat area covered with the resin film. Therefore, the solder bumpelectrodes are connected to the upper and side surfaces of the secondmetal film forming the upper layer of the UBM.

In the semiconductor device (electronic component) including the solderbump electrodes described in Japanese Unexamined Patent ApplicationPublication No. 2008-016514, it is feared that, for example, moisture inthe air enters the semiconductor device through gaps between the resinfilm (protective film) and portions of the solder bump electrodes thatare connected to the UBM, reaches the semiconductor element (functionalelement portion), and affects the characteristics of the electroniccomponent.

SUMMARY OF THE INVENTION

Preferred embodiments of the present invention provide electroniccomponents that each have improved moisture resistance.

An Electronic component according to a preferred embodiment of thepresent invention includes a substrate, a functional element portion, awiring layer, a cover portion, a connection electrode, an electricallyconductive layer, a protective film, a solder bump, and an alloy layer.The functional element portion is on a front surface side of thesubstrate. The wiring layer is on the front surface side of thesubstrate and is electrically connected to the functional elementportion. The cover portion is on the front surface side of the substrateand protects the functional element portion. The connection electrode ison the wiring layer and extends in a thickness direction of thesubstrate. The electrically conductive layer is on the cover portion andthe connection electrode and electrically connected to the wiring layervia the connection electrode. The protective film covers the coverportion and the electrically conductive layer and includes an opening ina projection region of a portion of the electrically conductive layer inthe thickness direction. The solder bump is electrically connected tothe electrically conductive layer via the opening. The alloy layer isprovided between the solder bump and the electrically conductive layerin the thickness direction to join the solder bump to the electricallyconductive layer and differs in at least one of composition and acombination of elements from the solder bump. The electronic componentincludes a plurality of sets of the wiring layer, the connectionelectrode, the electrically conductive layer, the solder bump, and thealloy layer. The protective film includes a plurality of the openingscorresponding to the plurality of sets. In at least one set of theplurality of sets, the connection electrode is structured such that atleast a portion thereof does not overlap the solder bump in a plan viewin the thickness direction. A surface of the electrically conductivelayer that is located on a protective film side is in contact with theprotective film in a region between the alloy layer and an edge of theelectrically conductive layer that is located on a connection electrodeside in a plan view in the thickness direction.

An electronic component according to a preferred embodiment of thepresent invention includes a substrate, a functional element portion, awiring layer, a cover portion, a connection electrode, an electricallyconductive layer, a protective film, a solder bump, and an alloy layer.The functional element portion is on a front surface side of thesubstrate. The wiring layer is on the front surface side of thesubstrate and electrically connected to the functional element portion.The cover portion is on the front surface side of the substrate andprotects the functional element portion. The connection electrode is onthe wiring layer and extends in a thickness direction of the substrate.The electrically conductive layer is on the connection electrode and aback surface of the substrate that is opposite to the front surfacethereof and electrically connected to the wiring layer via theconnection electrode. The protective film covers the back surface of thesubstrate and the electrically conductive layer and includes an openingin a projection region of a portion of the electrically conductive layerin the thickness direction. The solder bump is electrically connected tothe electrically conductive layer via the opening. The alloy layer isprovided between the solder bump and the electrically conductive layerin the thickness direction to join the solder bump to the electricallyconductive layer and differs in at least one of composition and acombination of elements from the solder bump. The electronic componentincludes a plurality of sets of the wiring layer, the connectionelectrode, the electrically conductive layer, the solder bump, and thealloy layer. The protective film includes a plurality of the openingscorresponding to the plurality of sets. In at least one set of theplurality of sets, the connection electrode is structured such that atleast a portion thereof does not overlap the solder bump in a plan viewin the thickness direction. A surface of the electrically conductivelayer that is located on a protective film side is in contact with theprotective film in a region between the alloy layer and an edge of theelectrically conductive layer that is located on a connection electrodeside in a plan view in the thickness direction.

In electronic components according to preferred embodiments of thepresent invention, moisture resistance thereof is able to be improved.

The above and other elements, features, steps, characteristics andadvantages of the present invention will become more apparent from thefollowing detailed description of the preferred embodiments withreference to the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view of an electronic component according topreferred embodiment 1 of the present invention.

FIG. 2 is a plan view of the electronic component.

FIG. 3 is a cross-sectional view illustrating a preferred embodiment ofa method for producing the electronic component.

FIG. 4 is a plan view illustrating the method for producing theelectronic component.

FIG. 5 is a cross-sectional view of an electronic component according tomodification 1 of preferred embodiment 1 of the present invention.

FIG. 6 is a plan view of the electronic component.

FIG. 7A is a cross-sectional view of an electronic component accordingto modification 2 of preferred embodiment 1 of the present invention.FIG. 7B is an enlarged view of an essential portion of FIG. 7A.

FIG. 8 is a cross-sectional view of an electronic component according topreferred embodiment 2 of the present invention.

FIG. 9 is a cross-sectional view illustrating a preferred embodiment ofa method for producing the electronic component.

FIG. 10 is a cross-sectional view of an electronic component accordingto preferred embodiment 3 of the present invention.

FIG. 11 is a cross-sectional view of an electronic component accordingto preferred embodiment 4 of the present invention.

FIG. 12A is a cross-sectional view of an electronic component accordingto a modification of preferred embodiment 4 of the present invention.FIG. 12B is an enlarged view of an essential part of FIG. 12A.

FIG. 13 is a cross-sectional view of an electronic component accordingto preferred embodiment 5 of the present invention.

FIG. 14 is a cross-sectional view of an electronic component accordingto preferred embodiment 6 of the present invention.

FIG. 15 is a cross-sectional view of an electronic component accordingto preferred embodiment 7 of the present invention.

FIG. 16 is a cross-sectional view of an electronic component accordingto preferred embodiment 8 of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Electronic components according to preferred embodiments of the presentinvention will be described in detail with reference to the drawings.

FIGS. 1 to 16 referred to in the preferred embodiments below etc. areschematic illustrations, and the ratios of sizes and thicknesses ofelements and portions in the drawings do not always reflect actualdimensional ratios.

Preferred Embodiment 1 (1) Overall Structure of Electronic Component

An electronic component 100 according to preferred embodiment 1 of thepresent invention will be described with reference to the drawings.

As shown in FIGS. 1 and 2, the electronic component 100 according topreferred embodiment 1 preferably includes a substrate 1, a plurality of(e.g., two) functional element portions 2, a plurality of (e.g., four)wiring layers 3, a cover portion 4, a plurality of (4 in the exampleshown) connection electrodes 5, a plurality of (4 in the example shown)electrically conductive layers 6, a protective film 7, a plurality of (4in the example shown) solder bumps 8, and a plurality of (4 in theexample shown) alloy layers 9. FIG. 1 is a cross-sectional view takenalong line X1-X1 in FIG. 2. The plurality of solder bumps 8 are usedwhen the electronic component 100 is mounted on a mounting substrate.When the electronic component 100 is mounted on the mounting substrate,the plurality of solder bumps 8 are electrically and mechanicallyconnected to the mounting substrate. The mounting substrate ispreferably, for example, a printed wiring board or a LTCC (LowTemperature Co-fired Ceramic).

The substrate 1 includes a front surface (first principal surface) 11and a back surface (second principal surface) 12 that are opposite toeach other in a thickness direction D1 of the substrate 1. Thefunctional element portions 2 are on the front surface 11 side of thesubstrate 1. The plurality of wiring layers 3 are on the front surface11 side of the substrate 1 and electrically connected to the functionalelement portions 2. In the electronic component 100 according topreferred embodiment 1, two wiring layers 3 are electrically connectedto each of the two functional element portions 2.

The cover portion 4 is on the front surface 11 side of the substrate 1and protects the functional element portions 2. In the electroniccomponent 100 according to preferred embodiment 1, the plurality ofconnection electrodes 5 correspond one-to-one to the plurality of wiringlayers 3. Each of the plurality of connection electrodes 5 preferably ison a corresponding one of the wiring layers 3 and extends in thethickness direction D1 of the substrate 1.

In the electronic component 100 according to preferred embodiment 1, theplurality of electrically conductive layers 6 correspond one-to-one tothe plurality of connection electrodes 5. The electrically conductivelayers 6 are on the cover portion 4 and the connection electrodes 5 andelectrically connected to the wiring layers 3 via the connectionelectrodes 5.

The protective film 7 covers the cover portion 4 and the plurality ofelectrically conductive layers 6. The protective film 7 includes aplurality of openings 71. The plurality of openings 71 correspondone-to-one to the plurality of electrically conductive layers 6. Each ofthe plurality of openings 71 in the protective film 7 is preferablyprovided in a projection region of a portion of a corresponding one ofthe plurality of electrically conductive layers 6 in the thicknessdirection D1 of the substrate 1.

The plurality of solder bumps 8 correspond one-to-one to the pluralityof electrically conductive layers 6. The plurality of solder bumps 8 aresurrounded by the protective film 7. Each of the plurality of solderbumps 8 is electrically connected to a corresponding one of theelectrically conductive layers 6 via a corresponding one of the openings71. Each alloy layer 9 is provided between a corresponding solder bump 8and a corresponding electrically conductive layer 6 in the thicknessdirection D1 of the substrate 1 to join the solder bump 8 to theelectrically conductive layer 6. The alloy layers 9 preferably differ inat least one of composition and a combination of elements from thesolder bumps 8. In the electronic component 100 according to preferredembodiment 1, both the composition and the combination of the alloylayers 9 preferably differ from those of the solder bumps 8.

The electronic component 100 according to preferred embodiment 1 ispreferably an acoustic wave device that uses acoustic waves. Each of thefunctional element portions 2 includes an IDT (Interdigital Transducer)electrode 21. The electronic component 100 according to preferredembodiment 1 includes a space S1 surrounded by the substrate 1 and thecover portion 4. The IDT electrodes 21 are in the space S1.

(2) Elements of Electronic Component

Next, the elements of the electronic component 100 will be describedwith reference to the drawings.

The shape of the substrate 1 in a plan view (the outer circumferentialshape of the substrate 1 when viewed in the thickness direction D1) ispreferably square or substantially square, but is not limited to thesquare shape and may be rectangular or substantially rectangular, or anyother desirable shape. In the electronic component 100 according topreferred embodiment 1, the substrate 1 has piezoelectricity at least inregions in which the IDT electrodes 21 are provided. The substrate 1 isa piezoelectric substrate. The piezoelectric substrate is preferably aLiNb03 substrate, for example, but this is not a specific requirement asthe substrate 1 may be, for example, a LiTa03 substrate, a ZnOsubstrate, an AIN substrate, etc. In the electronic component 100according to preferred embodiment 1, the substrate 1 has electricalinsulating properties at least in the regions in which the IDTelectrodes 21 are provided.

The functional element portions 2 are on the front surface 11 side ofthe substrate 1. More particularly, the functional element portions 2include the respective IDT electrodes on the front surface 11 of thesubstrate 1. The IDT electrodes are supported on the substrate 1. EachIDT electrode is a functional electrode that converts an acoustic wavepropagating through the substrate 1 to an electric signal or converts anelectric signal to an acoustic wave. Each IDT electrode 21 canpreferably be made of a suitable metal material such as, for example,Al, Cu, Pt, Au, Ag, Ti, Ni, Cr, Mo, W, or an alloy composed mainly ofany of these metals. Each IDT electrode 21 may have a structure formedby stacking a plurality of metal films formed of any of these metals oran alloy thereof.

Each of the IDT electrodes 21 preferably includes a first busbar, asecond busbar, a plurality of first electrode fingers 221, and aplurality of second electrode fingers 222.

The first and second busbars each have an elongated shape having alongitudinal direction extending in a second direction D2 of thesubstrate 1 orthogonal or substantially orthogonal to its thicknessdirection D1 (first direction). In each IDT electrode 21, the first andsecond busbars oppose each other in a third direction D3 (see FIG. 2)orthogonal or substantially orthogonal to both the first direction (thethickness direction D1 of the substrate 1) and the second direction D2.

The plurality of first electrode fingers 221 are connected to the firstbusbar and extend toward the second busbar. The plurality of firstelectrode fingers 221 extend from the first busbar in a direction (thethird direction D3) orthogonal or substantially orthogonal to thelongitudinal direction of the first busbar (the second direction D2).The forward ends of the plurality of first electrode fingers 221 arespaced apart from the second busbar. For example, the plurality of firstelectrode fingers 221 preferably have the same or substantially the samelength and the same or substantially the same width.

The plurality of second electrode fingers 222 are connected to thesecond busbar and extend toward the first busbar. The plurality ofsecond electrode fingers 222 extend from the second busbar in adirection (the third direction D3) orthogonal or substantiallyorthogonal to the longitudinal direction (the second direction D2) ofthe second busbar. The forward ends of the plurality of second electrodefingers 222 are spaced apart from the first busbar. For example, theplurality of second electrode fingers 222 preferably have the same orsubstantially the same length and the same or substantially the samewidth.

In each of the IDT electrodes 21, the plurality of first electrodefingers 221 and the plurality of second electrode fingers 222 arearranged alternately in the second direction D2 so as to be spaced fromeach other. Therefore, each first electrode finger 221 and acorresponding second electrode finger 222 adjacent thereto in the seconddirection D2 are spaced apart from each other. The period of theelectrode fingers of each IDT electrode 21 is defined, for example, asthe distance between center lines of two adjacent first electrodefingers 221 or the distance between center lines of two adjacent secondelectrode fingers 222 and is twice the distance between one side edge ofa first electrode finger 221 and a corresponding side edge of anadjacent second electrode finger 222.

The wiring layers 3 are on the front surface 11 side of the substrate 1.More particularly, the wiring layers 3 are on the front surface 11 ofthe substrate 1. The wiring layers 3 electrically connect the connectionelectrodes 5 to the functional element portions 2. The wiring layers 3can preferably be made of an appropriate metal material such as, forexample, Al, Cu, Pt, Au, Ag, Ti, Ni, Cr, Mo, W, or an alloy composedmainly of any of these metals. The wiring layers 3 may have a structuredefined by stacking a plurality of metal films made of any of thesemetals or an alloy thereof.

The wiring layers 3 overlap a portion of the functional element portions2 and a portion of the substrate 1 in the thickness direction D1 of thesubstrate 1. Each of the wiring layers 3 includes a first connectionportion and a second connection portion 32. The first connection portionis connected to a corresponding functional element portion 2. Moreparticularly, the first connection portion is connected to the firstbusbar or the second busbar of a corresponding IDT electrode 21. Thesecond connection portion 32 is connected to a corresponding connectionelectrode 5. The second connection portion 32 is interposed between thesubstrate 1 and the cover portion 4. The second connection portion 32 islocated inward of the outer circumference of the cover portion 4.

The cover portion 4 is on the front surface 11 side of the substrate 1and protects the functional element portions 2. More particularly, thecover portion 4 is on the front surface 11 side of the substrate 1 sideso as to cover the functional element portions 2. The cover portion 4covers the functional element portions 2 so as not to be in contact withthe IDT electrodes 21 of the functional element portions 2.Specifically, the cover portion 4 is not in contact with the IDTelectrodes 21 of the functional element portions 2. The cover portion 4protects the functional element portions 2 from an external impact,moisture, etc.

The cover portion 4 preferably includes a cover layer 42 and a spacerlayer 41. The cover layer 42 opposes the substrate 1 in the thicknessdirection D1 of the substrate 1 and is spaced apart from the functionalelement portions 2. The spacer layer 41 has a frame shape. The spacerlayer 41 is interposed between the substrate 1 and the cover layer 42.The spacer layer 41 surrounds the functional element portions 2 in aplan view in the thickness direction D1. In the electronic component100, the atmosphere in the space S1 surrounded by the cover layer 42,the spacer layer 41, and the substrate 1 is preferably, for example,air, but this is not a limitation. The atmosphere may be, for example,an inert gas atmosphere. The inert gas is preferably, for example, N2gas.

The cover layer 42 has a flat plate shape. The shape of the cover layer42 in a plan view (the outer circumferential shape when viewed in thethickness direction D1 of the substrate 1) is preferably a square orsubstantially square shape but is not limited to the square orsubstantially square shape and may be, for example, a rectangular orsubstantially rectangular shape, or any other desirable shape. The outercircumferential shape of the cover layer 42 is smaller than the outercircumferential shape of the substrate 1. The outer circumferentialshape of the cover layer 42 is smaller than the outer circumferentialshape of the spacer layer 41 and larger than the inner circumferentialshape of the spacer layer 41. The cover layer 42 is on the spacer layer41. The cover layer 42 is spaced apart from the IDT electrodes 21 in thethickness direction D1. The cover layer 42 has electrical insulatingproperties. The material of the cover layer 42 is preferably, forexample, a synthetic resin such as an epoxy resin, a polyimide resin, oran acrylic resin.

The spacer layer 41 is provided along the outer circumference of thesubstrate 1 in a plan view. The shape of the spacer layer 41 in a planview is a frame shape. The outer circumferential shape of the spacerlayer 41 is preferably, for example, a square or substantially squareshape. The inner circumferential shape of the spacer layer 41 ispreferably, for example, a square or substantially square shape. Theouter circumferential shape of the spacer layer 41 is smaller than theouter circumferential shape of the substrate 1. The spacer layer 41covers a portion of the second connection portions 32 of the wiringlayers 3. Specifically, the spacer layer 41 includes a first portionprovided directly on the front surface 11 of the substrate 1 and asecond portion provided indirectly on the front surface 11 of thesubstrate 1 with the second connection portions 32 interposedtherebetween. The first portion is provided along the entire orsubstantially the entire outer circumference of the substrate 1.

The spacer layer 41 has electrical insulating properties. The materialof the spacer layer 41 is preferably, for example, a synthetic resinsuch as an epoxy resin, a polyimide resin, or an acrylic resin. In thecover portion 4, the cover layer 42 is bonded directly to the spacerlayer 41. Preferably, the main component of the material of the spacerlayer 41 is the same as the main component of the material of the coverlayer 42. More preferably, the material of the spacer layer 41 is thesame as the material of the cover layer 42.

The thickness of the spacer layer 41 is larger than the sum of thethickness of the IDT electrodes 21 and the thickness of the wiringlayers 3.

The electronic component 100 preferably includes a plurality of sets ofthe wiring layer 3, the connection electrode 5, the electricallyconductive layer 6, the solder bump 8, and the alloy layer 9. In each ofthe plurality of sets, the connection electrode 5 is a through electrodepassing through the cover portion 4 in the thickness direction D1 of thesubstrate 1. More particularly, the connection electrode 5 passesthrough the spacer layer 41 and the cover layer 42. The connectionelectrode 5 is provided on the second connection portion 32 of thewiring layers 3 and electrically connected to the second connectionportion 32.

The connection electrode 5 can preferably be made of an appropriatemetal material such as, for example, Cu, Ni, or an alloy composed mainlyof any of these metals.

The connection electrode 5 is provided such that at least a portionthereof does not overlap the solder bump 8 in a plan view in thethickness direction D1 of the substrate 1. In the electronic component100 according to preferred embodiment 1, the connection electrode 5 isstructured such that the entire or substantially the entire connectionelectrode 5 does not overlap the solder bump 8 in a plan view in thethickness direction D1. Specifically, the connection electrode 5 isspaced apart from the solder bump 8 in a plan view in the thicknessdirection D1.

The electrically conductive layers 6 are on the cover portion 4 and onthe connection electrodes 5. The plurality of electrically conductivelayers 6 are preferably spaced apart from each other on the coverportion 4. Therefore, the plurality of electrically conductive layers 6are electrically insulated from each other. In each of the plurality ofsets, the electrically conductive layer 6 is electrically connected tothe wiring layer 3 via the connection electrode 5. The electricallyconductive layer 6 is a rewiring layer and includes a first connectionportion 65 connected to the connection electrode 5, a second connectionportion 68 connected to the solder bump 8 with the alloy layer 9interposed therebetween, and an intermediate portion 66 between thefirst connection portion 65 and the second connection portion 68. Aportion of the first connection portion 65 overlaps the connectionelectrode 5 in the thickness direction D1 of the substrate 1. The firstconnection portion 65 is in contact with an end surface of theconnection electrode 5 that is opposite to the wiring layer 3 side. Aportion of the second connection portion 68 overlaps the alloy layer 9and the solder bump 8 in the thickness direction D1 of the substrate 1.The shape of the first connection portion 65 in a plan view (its outercircumferential shape when viewed in the thickness direction D1 of thesubstrate 1) is a square shape, but is not limited to the square shape,and may be, for example, a rectangular shape, a circular shape, etc. Theshape of the second connection portion 68 in a plan view (its outercircumferential shape when viewed in the thickness direction D1 of thesubstrate 1) is preferably a rectangular or substantially rectangularshape, but is not limited to the rectangular or substantiallyrectangular shape, and may be, for example, a square shape, a circularshape, etc.

The electrically conductive layer 6 preferably includes a first layer61, a second layer 62, and a third layer 63 that are stacked from theside close to the cover portion 4. From the viewpoint of reducing theelectric resistance of the electrically conductive layer 6, the firstlayer 61 is preferably, for example, a Cu layer. From the viewpoint ofpreventing diffusion of the solder (e.g., SnAgCu) in the solder bump 8,the second layer 62 is preferably, for example, a Ni layer.Specifically, it is preferable that the second layer 62 defines andfunctions as a barrier metal layer. Moreover, the second layer 62preferably defines and functions as an under bump metal. The third layer63 is preferably, for example, an Au layer. The third layer 63 surroundsthe entire or substantially the entire circumference of the alloy layer9.

The thickness of the electrically conductive layer 6 is preferably, forexample, about 13.1 μm. The thickness of the first layer 61, thethickness of the second layer 62, and the thickness of the third layer63 are, for example, preferably about 10 μm, about 3 μm, and about 0.1μm, respectively. These thicknesses of the first layer 61, the secondlayer 62, and the third layer 63 are examples, and no particularlimitation is imposed on the thicknesses.

In each of the plurality of sets, the electrically conductive layer 6 isin contact with the protective film 7 in a region between the alloylayer 9 and an edge 602 on the connection electrode 5 side in a planview in the thickness direction D1. In this region, the electricallyconductive layer 6 and the protective film 7 are in close contact witheach other.

Moreover, the electrically conductive layer 6 is in contact with theprotective film 7 in a region between the outer circumference of thesecond connection portion 68 and the alloy layer 9 in a plan view in thethickness direction D1. In this region, the electrically conductivelayer 6 and the protective film 7 are in close contact with each other.

The protective film 7 covers a surface 401 of the cover portion 4 thatis opposite to the substrate 1 side, surfaces (first principal surfaces)601 of the plurality of electrically conductive layers 6 that are on theprotective film 7 side, and their outer circumferential surfaces 603.Moreover, the protective film 7 covers surfaces 901 of the plurality ofalloy layers 9 that are on the protective film 7 side. The outercircumferential shape of the protective film 7 is smaller than the outercircumferential shape of the cover layer 42. The protective film 7protects the plurality of electrically conductive layers 6 from anexternal impact, moisture, etc. , for example.

The protective film 7 includes a plurality of openings 71 thatcorrespond to the plurality of sets. Each of the plurality of openings71 of the protective film 7 is provided in a projection region of aportion of the second connection portion 68 of a corresponding one ofthe plurality of electrically conductive layers 6. The opening shape ofthe openings 71 is preferably, for example, a rectangular orsubstantially rectangular shape, but this is not a specific requirement.The opening shape may be, for example, a square shape, a circular shape,etc. In a plan view in the thickness direction D1 of the substrate 1,the openings 71 are smaller than the second connection portions 68 ofthe electrically conductive layers 6. In a plan view in the thicknessdirection D1 of the substrate 1, the openings 71 are smaller than thealloy layers 9.

The protective film 7 has electrical insulating properties. Theprotective film 7 is preferably made of a material having lowerwettability with respect to the solder (e.g., SnAgCu) in the solderbumps 8 than the electrically conductive layers 6. The wettability ofthe protective film 7 is lower than the wettability of the third layers63 of the electrically conductive layers 6. The protective film 7 ispreferably, for example, a polyimide resin, but is not limited thereto,and may be, for example, an epoxy resin, an acrylic resin, etc.

The material of the solder bumps 8 is preferably lead-free solder, forexample. More particularly, the material of the solder bumps 8 ispreferably, for example, SnAgCu. The material of the solder bumps 8 isnot limited to SnAgCu and may be, for example, SnAg.

In each of the plurality of sets, the solder bump 8 is electricallyconnected to the electrically conductive layer 6 via the opening 71. Thesolder bump 8 is joined to the electrically conductive layer 6 with thealloy layer 9 interposed therebetween. An end portion 81 of the solderbump 8 that is on the electrically conductive layer 6 side in thethickness direction D1 of the substrate 1 is in the opening 71. Theouter circumferential surface of the end portion 81 of the solder bumps8 is in contact with the inner circumferential surface of the opening 71of the protective film 7.

In a plan view in the thickness direction D1 of the substrate 1, thesolder bump 8 overlaps the entire or substantially the entire opening 71of the protective film 7. In other words, the solder bump 8 covers theopening 71 in a plan view in the thickness direction D1 of the substrate1.

The plurality of solder bumps 8 are arranged so as to be spaced apartfrom each other in a direction along the outer circumference of theprotective film 7. The plurality of solder bumps 8 are provided near therespective four corners of the protective film 7 in a plan view in thethickness direction D1 of the substrate 1.

In each of the plurality of sets in the electronic component 100, theelectrically conductive layer 6 and the solder bump 8 are joined withthe alloy layer 9 interposed therebetween. The alloy layer 9 preferablyincludes, for example, Sn and Au as elements. Both the composition and acombination of elements of the alloy layer 9 differ from those of thesolder bump 8. The alloy layer 9 is formed by, for example, the reactionbetween the solder melted during reflow treatment (hereinafter referredto as “molten solder”) and an electrically conductive layer 60 (seeFIGS. 3 and 4) in the course of production of the electronic component100. More particularly, the alloy layer 9 is formed by the reactionbetween the molten solder and a third layer 630 (Au seed layer) of theelectrically conductive layer 60 formed before the reflow treatment.

As shown in FIG. 3, the electrically conductive layer preferably has amultilayer structure including the first layer 61, the second layer 62,and the third layer 630. As shown in FIGS. 3 and 4, in the electricallyconductive layers 60, a portion of a surface of the third layer 630 thatis opposite to the second layer 62 side is exposed through the opening71. The first layer 61 and the second layer 62 in the electricallyconductive layer 60 are preferably the same as the first layer 61 andthe second layer 62 in the electrically conductive layer 6.Specifically, the first layer 61 and the second layer 62 in theelectrically conductive layer 60 are preferably, for example, a Cu layerand a Ni layer, respectively. The material and thickness of the thirdlayer 630 in the electrically conductive layer 60 are the same as thematerial and thickness of the third layer 63 in the electricallyconductive layer 6. The third layer 630 in the electrically conductivelayer 60 is preferably, for example, an Au layer.

The thickness of the alloy layer 9 is larger than the thickness of thethird layer 63. As shown in FIGS. 1 and 2, the alloy layer 9 isconnected to the third layer 63 of the electrically conductive layer 6in in-plane directions orthogonal to the thickness direction D1 of thesubstrate 1. The alloy layer is connected to the second layer 62 of theelectrically conductive layer 6 and the solder bump 8 in the thicknessdirection D1 of the substrate 1.

The alloy layer 9 is larger than the opening 71 in a plan view in thethickness direction D1 of the substrate 1. The alloy layer 9 preferablyincludes a base portion 90 that is a portion of the alloy layer 9provided within the thickness of the electrically conductive layer 6;and a protruding portion 91 protruding from the base portion 90 towardthe solder bump 8 in the thickness direction D1 of the substrate 1. Theprotruding portion 91 is located within the opening 71 of the protectivefilm 7. The outer circumferential shape of the protruding portion 91 ispreferably the same or substantially the same as the outercircumferential shape of the end portion 81 of the solder bump 8. Theouter circumferential surface of the protruding portion 91 is in contactwith the inner circumferential surface of the opening 71 in theprotective film 7. An extending portion 900 of the base portion 90 (aportion of the alloy layer 9) that surrounds the protruding portion 91in a plan view in the thickness direction D1 of the substrate 1 islocated between the protective film 7 and the second layer 62 of theelectrically conductive layer 6 in the thickness direction D1 of thesubstrate 1.

(3) Method for Producing Electronic Component

An example of a preferred embodiment of a method for producing theelectronic component 100 will be described briefly.

In the method for producing the electronic component 100, the substrate1 is first prepared, and then a first step to an eighth step areperformed.

In the first step, the functional element portions 2 are formed on thefront surface 11 side of the substrate 1. More particularly, in thefirst step, the functional element portions 2 each including the IDTelectrode 21 are preferably formed by a lift-off method using aphotolithography technique and a thin film forming technique. In thesecond step, the wiring layers 3 are formed on the front surface 11 sideof the substrate 1. In the third step, the spacer layer 41 is formed onthe front surface 11 side of the substrate 1 using, for example, a spincoating technique, the photolithography technique, etc. In the thirdstep, the frame-shaped spacer layer 41 is formed, and, at the same time,first through holes are formed in the spacer layer 41 at positions inwhich the connection electrodes 5 are to be formed. In the fourth step,the cover layer 42 formed of a photosensitive resin film is bonded tothe spacer layer 41 using a lamination technique. In the fifth step, thephotolithography technique is used to form second through holes in thecover layer 42 at positions in which the connection electrodes 5 are tobe formed. At this point, the second through holes are connected to thefirst through holes. In the sixth step, the connection electrodes 5 areformed by, for example, plating. In the seventh step, the electricallyconductive layers 60 are formed by, for example, plating. In the eighthstep, the spin coating technique, the photolithography technique, etc.are used to form the protective film 7 including the openings 71 to thusobtain the structure shown in FIGS. 3 and 4. In the eighth step, reflowtreatment is performed to form the solder bumps 8 and the alloy layers9. In the eighth step, for example, a solder paste is applied to thesurfaces of the electrically conductive layers 60 and then melted in areflow furnace to form the solder bumps 8 and the alloy layers 9.

In the method for producing the electronic component 100, a wafer onwhich a plurality of electronic components 100 can be formed is used asthe substrate 1 in the first step to the eighth step. After the eighthstep, a dicing step is performed to cut the wafer with a dicing machine,so that a plurality of electronic components 100 can be obtained fromone wafer. In the dicing step, the dicing machine used is, for example,a dicing saw, a laser, etc.

(4) Relationship Among Connection Electrodes, Solder Bumps, ElectricallyConductive Layers, Alloy Layers, and Protective Film

As described above, the electronic component 100 preferably includes theplurality of sets of the wiring layer 3, the connection electrode 5, theelectrically conductive layer 6, the solder bump 8, and the alloy layer9. In each of the plurality of sets, the connection electrode 5 isstructured such that at least a portion thereof does not overlap thesolder bump 8 in a plan view in the thickness direction D1. In theelectronic component 100 according to preferred embodiment 1, theconnection electrode 5 is preferably spaced apart from the solder bump 8in a plan view in the thickness direction D1 of the substrate 1.Therefore, in the electronic component 100 according to preferredembodiment 1, the connection electrode 5 is spaced apart from the solderbump 8 in the second direction D2. In the electronic component 100according to preferred embodiment 1, as the distance between theconnection electrode 5 and the solder bump 8 in a plan view in thethickness direction D1 increases, the length of a portion of theelectrically conductive layer 6 that overlaps the protective film 7 inthe thickness direction D1 of the substrate 1 increases.

The alloy layer 9 is formed by the reaction between molten solder(molten SnAgCu) and the third layer 630 (Au layer) of the electricallyconductive layer 60 during the reflow treatment. Therefore, the alloylayer 9 may be peeled off the protective film 7, and a gap may be formedbetween the alloy layer 9 and the protective film 7. However, theelectrically conductive layer 6 is in contact with the protective film 7in a region between the alloy layer 9 and the edge 602 on the connectionelectrode 5 side in a plan view in the thickness direction D1. A portionof the protective film 7 is stacked on the region of the electricallyconductive layer 6 that is located between the alloy layer 9 and theedge 602 on the connection electrode 5 side in a plan view in thethickness direction D1, and the protective film 7 and the electricallyconductive layer 6 are in close contact with each other in this region.Specifically, the adhesion between the protective film 7 and the regionof the electrically conductive layer 6 that is located between the alloylayer 9 and the edge 602 on the connection electrode 5 side in a planview in the thickness direction D1 is substantially determined by, forexample, the conditions when the protective film 7 is stacked on theelectrically conductive layer 60 (components of a resin material thatforms the protective film 7, the application conditions, the surfacestate and surface morphology of the electrically conductive layer 60).

The electrically conductive layer 6 surrounds the entire orsubstantially the entire circumference of the alloy layer 9 in a planview in the thickness direction D1 of the substrate 1. A portion of thealloy layer 9 (the extending portion 900) is interposed between theprotective film 7 and the cover portion 4 in the thickness direction D1of the substrate 1. The length L6 of a portion of the electricallyconductive layer 6 that overlaps the protective film 7 in the regionbetween the alloy layer 9 and the edge 602 on the connection electrode 5side in a plan view in the thickness direction D1 of the substrate 1 ispreferably larger than the length L9 of a portion (the extending portion900) of the alloy layer 9 that overlaps the protective film 7.

Moreover, the length L68 of a portion of the electrically conductivelayer 6 that overlaps the protective film 7 in the second connectionportion 68 is preferably larger than the length L9 of the portion (theextending portion 900) of the alloy layer 9 that overlaps the protectivefilm 7. The length L6 is larger than the thickness of the electricallyconductive layer 6. The length L68 is larger than the thickness of theelectrically conductive layer 6 (in FIG. 1, the thickness of theelectrically conductive layer 6 drawn is exaggerated).

In the electronic component 100 according to preferred embodiment 1, themaximum height roughness of the surface 601 of the electricallyconductive layer 6 that is on the protective film 7 side is larger thanthe maximum height roughness of the surface 901 of the alloy layer 9that is on the protective film 7 side.

The maximum height roughness is preferably, for example, about 1.6 μm.From the viewpoint of improving the adhesion between the electricallyconductive layer 6 and the protective film 7, it is preferable that themaximum height roughness is preferably, for example, about 1 μm or more.The maximum height roughness is a value measured from a cross-sectionalSEM (scanning electron microscope) image. The magnification of thecross-sectional SEM image when the maximum height roughness is measuredis, for example, 10000×. The maximum height roughness is the sum of themaximum peak height and the maximum valley depth of the surface 601 ofthe electrically conductive layer 6 in the cross-sectional SEM image.The maximum height roughness of the surface 601 of the electricallyconductive layer 6 that is on the protective film 7 side can be changedby, for example, changing the plating conditions for the second layer 62in the course of production. Alternatively, the maximum height roughnessof the surface 601 of the electrically conductive layer 6 that is on theprotective film 7 side can be changed by subjecting the first layer 61to etching or sandblast treatment in the course of production. In thiscase, since the second layer 62 and the third layer 63 are stacked onthe surface of the first layer 61 subjected to the etching or sandblasttreatment, the second layer 62 and the third layer 63 are also coarsenedaccordingly.

(4) Advantageous Effects

The electronic component 100 according to preferred embodiment 1includes the substrate 1, the functional element portions 2, the wiringlayers 3, the cover portion 4, the connection electrodes 5, theelectrically conductive layers 6, the protective film 7, the solderbumps 8, and the alloy layers 9. The functional element portions 2 areon the front surface 11 side of the substrate 1. The wiring layers 3 areon the front surface 11 side of the substrate 1 and are electricallyconnected to the functional element portions 2. The cover portion 4 ison the front surface 11 side of the substrate 1 and protects thefunctional element portions 2. The connection electrodes 5 are on thewiring layers 3 and extend in the thickness direction D1 of thesubstrate 1. The electrically conductive layers 6 are on the coverportion 4 and on the connection electrodes 5 and electrically connectedto the wiring layers 3 via the connection electrodes 5. The protectivefilm 7 covers the cover portion 4 and the electrically conductive layers6 and includes the openings 71 in the projection regions of a portion ofthe electrically conductive layers 6 in the thickness direction D1. Thesolder bumps 8 are electrically connected to the electrically conductivelayers 6 via the openings 71. The alloy layers 9 are provided betweenthe solder bumps 8 and the electrically conductive layers 6 in thethickness direction D1 to join the solder bumps 8 to the electricallyconductive layers 6, and the composition and the combination of elementsof the alloy layers 9 preferably differ from those of the solder bumps8. The electronic component 100 according to preferred embodiment 1includes the plurality of sets of the wiring layer 3, the connectionelectrode 5, the electrically conductive layer 6, the solder bump 8, andthe alloy layer 9. The protective film 7 includes the plurality ofopenings 71 corresponding to the plurality of sets. In at least one setof the plurality of sets (all the sets in this case), the connectionelectrode 5 is structured such that at least a portion thereof does notoverlap the solder bump 8 in a plan view in the thickness direction D1.The surface 601 of the electrically conductive layer 6 that is on theprotective film 7 side is in contact with the protective film 7 in theregion between the alloy layer 9 and the edge 602 on the connectionelectrode 5 side in a plan view in the thickness direction D1.

In each of the plurality of sets in the electronic component 100according to preferred embodiment 1, the surface 601 of the electricallyconductive layer 6 that is located on the protective film 7 side ispreferably in contact (e.g., close contact) with the protective film 7in a region between the alloy layer 9 and the edge 602 on the connectionelectrode 5 side in a plan view in the thickness direction D1.Therefore, even when moisture passes through a gap between the alloylayer 9 and the protective film 7, the moisture is unlikely to reach theconnection electrode 5, so that the moisture is unlikely to reach thefunctional element portions 2. The moisture resistance of the electroniccomponent 100 according to preferred embodiment 1 can thus be improved,and the reliability can be improved.

In each of the plurality of sets in the electronic component 100according to preferred embodiment 1, the connection electrode 5 isspaced apart from the solder bump 8 in a plan view in the thicknessdirection D1 of the substrate 1. Therefore, in the electronic component100 according to preferred embodiment 1, the distance from the solderbump 8 to the connection electrode 5 is longer than that when theconnection electrode 5 includes a portion overlapping the solder bump 8in a plan view in the thickness direction D1. In this case, moisturefrom the outside is unlikely to reach the connection electrode 5, andtherefore the moisture resistance can be improved.

In each of the plurality of sets in the electronic component 100according to preferred embodiment 1, the electrically conductive layer 6surrounds the entire or substantially the entire circumference of thealloy layer 9. Therefore, in the electronic component 100 according topreferred embodiment 1, the moisture resistance can be further improvedas compared with the case where the electrically conductive layer 6 doesnot surround the entire or substantially the entire circumference of thealloy layer 9.

In each of the plurality of sets in the electronic component 100according to preferred embodiment 1, at least a portion of the alloylayer 9 is interposed between the protective film 7 and the electricallyconductive layer 6 (the second layer 62 thereof) in the thicknessdirection D1 of the substrate 1. Therefore, in the electronic component100 according to preferred embodiment 1, the joint strength between thesolder bump 8 and the electrically conductive layer 6 can be improved ascompared with the case where at least a portion of the alloy layer 9 isnot interposed between the protective film 7 and the electricallyconductive layer 6 (the second layer 62 thereof) in the thicknessdirection D1 of the substrate 1.

In each of the plurality of sets in the electronic component 100according to preferred embodiment 1, the length L6 of the portion of theelectrically conductive layer 6 that overlaps the protective film 7 inthe region between the alloy layer 9 and the edge 602 on the connectionelectrode 5 side in a plan view in the thickness direction D1 of thesubstrate 1 is preferably larger than the length L9 of the portion ofthe alloy layer 9 that overlaps the protective film 7. Therefore, in theelectronic component 100 according to preferred embodiment 1, themoisture resistance can be further improved as compared with the casewhere the length L6 is equal to or smaller than the length L9.

In each of the plurality of sets in the electronic component 100according to preferred embodiment 1, the electrically conductive layer 6preferably includes the Au layer (the third layer 63) that overlaps theprotective film 7 in a plan view in the thickness direction D1 of thesubstrate 1. The Au layer (the third layer 63) is connected to the alloylayer 9. The alloy layer 9 preferably includes Au. Therefore, in theelectronic component 100 according to preferred embodiment 1, theweather resistance of the electrically conductive layer 6 and the alloylayer 9 can be improved.

In each of the plurality of sets in the electronic component 100according to preferred embodiment 1, the maximum height roughness of thesurface 601 of the electrically conductive layer 6 that is located onthe protective film 7 side is larger than the maximum height roughnessof the surface 901 of the alloy layer 9 that is located on theprotective film 7 side. Therefore, in the electronic component 100according to preferred embodiment 1, the moisture resistance can beimproved as compared with the case where the maximum height roughness ofthe surface 601 of the electrically conductive layer 6 that is locatedon the protective film 7 side is equal to or lower than the maximumheight roughness of the surface 901 of the alloy layer 9 that is locatedon the protective film 7 side.

In each of the plurality of sets in the electronic component 100according to preferred embodiment 1, the maximum height roughness of thesurface 601 of the electrically conductive layer 6 that is located onthe protective film 7 side is preferably about 1 μm or more, forexample. Therefore, in the electronic component 100 according topreferred embodiment 1, the moisture resistance can be improved ascompared with the case where the maximum height roughness of the surface601 of the electrically conductive layer 6 that is located on theprotective film 7 side is less than about 1 μm.

In each of the plurality of sets in the electronic component 100according to preferred embodiment 1, the solder bump 8 overlaps theentire or substantially the entire opening 71 in a plan view in thethickness direction D1 of the substrate 1. Therefore, in the electroniccomponent 100 according to preferred embodiment 1, the joint strengthbetween the solder bump 8 and the electrically conductive layer 6 can beimproved.

In the electronic component 100 according to preferred embodiment 1, thefunctional element portions 2 include the respective IDT electrodes 21.The substrate 1 has piezoelectricity at least in regions in which theIDT electrodes 21 are provided. The cover portion 4 includes the coverlayer 42 and the spacer layer 41. The cover layer 42 opposes thesubstrate 1 in the thickness direction D1 and is spaced apart from thefunctional element portions 2. The spacer layer 41 has a frame shape.The spacer layer 41 is interposed between the substrate 1 and the coverlayer 42 and surrounds the functional element portions 2 in a plan viewin the thickness direction D1. In each of the plurality of sets, theconnection electrode 5 passes through the cover portion 4 in thethickness direction D1. Therefore, in the electronic component 100according to preferred embodiment 1, moisture from the outside can beprevented from reaching the IDT electrodes 21, so that the moistureresistance can be improved. The connection electrodes 5 pass through thespacer layer 41 and the cover layer 42 in the thickness direction D1.Therefore, in the electronic component 100 according to preferredembodiment 1, moisture from the outside can be prevented from reachingthe IDT electrodes 21, so that the moisture resistance can be improved.

(5) Modifications of Preferred Embodiment 1

An electronic component 100 a according to modification 1 of preferredembodiment 1 will be described referring to FIGS. 5 and 6.

The electronic component 100 a according to modification of preferredembodiment 1 preferably includes a connection electrode 5 a instead ofone of the plurality of (four) connection electrodes 5 of the electroniccomponent 100 according to preferred embodiment 1 (see FIGS. 1 and 2).Moreover, the electronic component 100 a according to modification 1 ofpreferred embodiment 1 preferably includes a cover portion 4 a insteadof the cover portion 4 of the electronic component 100 according topreferred embodiment 1. The cover portion 4 a includes a spacer layer 41a and a cover layer 42 a. In the electronic component 100 a according tomodification 1 of preferred embodiment 1, the same elements and portionsas those in the electronic component 100 according to preferredembodiment 1 are denoted by the same symbols, and their description willbe omitted.

The shapes of the spacer layer 41 a and the cover layer 42 a are thesame or substantially the same as those of the spacer layer 41 and thecover layer 42. The materials of the spacer layer 41 a and the coverlayer 42 a are the same as the materials of the spacer layer 41 and thecover layer 42. The connection electrode 5 a is a through electrodepassing through the cover portion 4 a in the thickness direction D1 ofthe substrate 1. The connection electrode 5 a passes through the spacerlayer 41 a and the cover layer 42 a. The connection electrode 5 a isstructured such that a portion thereof does not overlap a solder bump 8in a plan view in the thickness direction D1 of the substrate 1. Themultilayer structure of an electrically conductive layer 6 a connectedto the connection electrode 5 a is the same as that of the electricallyconductive layers 6. Specifically, the electrically conductive layer 6 apreferably includes a first layer 61, a second layer 62, and a thirdlayer 63, as do the electrically conductive layers 6.

In the electronic component 100 a according to modification 1 ofpreferred embodiment 1, as in the electronic component 100 according topreferred embodiment 1, the electrically conductive layer 6 a isconnected to the connection electrode 5 a, and a surface 601 a of theelectrically conductive layer 6 a that is located on the protective film7 side is in contact (close contact) with the protective film 7 in aregion between an alloy layer 9 a and an edge 602 a on the connectionelectrode 5 a side in a plan view in the thickness direction D1.Therefore, the moisture resistance can be improved. Moreover, in theelectronic component 100 a according to modification 1 of preferredembodiment 1, as in the electronic component 100 according to preferredembodiment 1, the maximum height roughness of the surface 601 a of theelectrically conductive layer 6 a that is located on the protective film7 side is preferably larger than the maximum height roughness of asurface 901 a of the alloy layer 9 a that is located on the protectivefilm 7 side.

In the electronic component 100 a according to modification 1 ofpreferred embodiment 1, the electrically conductive layer 6 a includesan extending portion 67 extending from the first connection portion 65toward the side opposite to the second connection portion 68 in a planview in the thickness direction D1 of the substrate 1. Therefore, in theelectronic component 100 a according to modification 1 of preferredembodiment 1, the moisture resistance can be improved as compared withthe case where the extending portion 67 is not included.

An electronic component 100 b according to modification 2 of preferredembodiment 1 will be described referring to FIGS. 7A and 7B.

The electronic component 100 b according to modification 2 of preferredembodiment 1 preferably includes a plurality of electrically conductivelayers 6 b instead of the plurality of electrically conductive layers 6of the electronic component 100 according to preferred embodiment 1 (seeFIGS. 1 and 2). In the electronic component 100 b according tomodification 2 of preferred embodiment 1, the same elements and portionsas those in the electronic component 100 according to preferredembodiment 1 are denoted by the same symbols, and their description willbe omitted.

Each of the electrically conductive layers 6 b of the electroniccomponent 100 b according to modification 2 preferably includes, inaddition to the first layer 61, the second layer 62, and the third layer63, a close contact layer 64. The close contact layer 64 is interposedbetween the third layer 63 and the protective film 7. The close contactlayer 64 has higher adhesion to the protective film 7 than the thirdlayer 63.

In the electronic component 100 b according to modification 2 ofpreferred embodiment 1, the protective film 7 preferably includes onematerial selected from the group consisting of an epoxy resin, apolyimide resin, and an acrylic resin, for example. The close contactlayer 64 preferably includes one material selected from the groupconsisting of Ti, Cr, and NiCr, for example.

In the electronic component 100 b according to modification 2 ofpreferred embodiment 1, as in the electronic component 100 according topreferred embodiment 1, a surface 601 b of each of the electricallyconductive layers 6 b that is located on the protective film 7 side isin contact (close contact) with the protective film 7 in a regionbetween a corresponding alloy layer 9 and an edge 602 b on theconnection electrode 5 side in a plan view in the thickness directionD1, and therefore the moisture resistance can be improved. In theelectronic component 100 b according to modification 2 of preferredembodiment 1, the electrically conductive layers 6 b include therespective close contact layers 64. Therefore, the adhesion between theprotective film 7 and the surface 601 b of each electrically conductivelayer 6 b that is located on the protective film 7 side in the thicknessdirection D1 of the substrate 1 can be improved, so that the moistureresistance can be further improved. In the electronic component 100 baccording to modification 2 of preferred embodiment 1, as in theelectronic component 100 according to preferred embodiment 1, themaximum height roughness of the surfaces 601 b of the electricallyconductive layers 6 b that are located on the protective film 7 side islarger than the maximum height roughness of surfaces 901 b of alloylayers 9 b that are located on the protective film 7 side.

Preferred Embodiment 2

An electronic component 100 c according to preferred embodiment 2 of thepresent invention will be described on the basis of FIG. 8.

The electronic component 100 c according to preferred embodiment 2preferably includes a plurality of electrically conductive layers 6 cinstead of the plurality of electrically conductive layers 6 of theelectronic component 100 according to preferred embodiment 1 (see FIGS.1 and 2). In the electronic component 100 c according to preferredembodiment 2, the same elements and portions as those in the electroniccomponent 100 according to preferred embodiment 1 are denoted by thesame symbols, and their description will be omitted.

The electrically conductive layers 6 c preferably include Cu, forexample. More particularly, each of the electrically conductive layers 6c is preferably a Cu layer. Specifically, although the electricallyconductive layers 6 of the electronic component 100 according topreferred embodiment 1 each have a multilayer structure, theelectrically conductive layers 6 c in preferred embodiment 2 each have asingle layer structure. The electrically conductive layers 6 cpreferably include Cu as a base material, and any impurities may beadded, for example.

In the electronic component 100 c, the electrically conductive layers 6c are joined to the respective solder bumps 8 with respective alloylayers 9 c interposed therebetween. The alloy layers 9 c preferablyinclude Sn and Cu, for example, as elements. The alloy layers 9 c differin at least composition from the solder bumps 8. Each alloy layer 9 c isformed by the reaction between an electrically conductive layer 60 c(see FIG. 9) and melted solder (hereinafter referred to as “moltensolder”) melted during reflow treatment in the course of production ofthe electronic component 100 c. More particularly, each alloy layer 9 cis formed by the reaction between the molten solder and the electricallyconductive layer 60 c (Cu layer) formed before the reflow treatment.

The electrically conductive layers 60 c are each preferably a single Culayer, for example. As shown in FIG. 9, a portion of surfaces of theelectrically conductive layers 60 c that are located on the sideopposite to the cover portion 4 are exposed through the respectiveopenings 71. The material and thickness of the electrically conductivelayers 60 c are the same or substantially the same as the material andthickness of the electrically conductive layers 6 c.

As shown in FIG. 8, the alloy layers 9 c are formed in the electricallyconductive layers 6 c so as to extend to intermediate positions in thethickness direction and do not pass through the electrically conductivelayers 6 c. The alloy layers 9 c are connected to the electricallyconductive layers 6 c in in-plane directions orthogonal or substantiallyorthogonal to the thickness direction D1 of the substrate 1. The alloylayers 9 c are connected, in the thickness direction D1 of the substrate1, to the solder bumps 8 and portions of the electrically conductivelayers 6 c that are located directly below the alloy layers 9 c.

The alloy layers 9 c are larger than the openings 71 in a plan view inthe thickness direction D1 of the substrate 1. Each alloy layer 9 cincludes a base portion 90 c that is a portion of the alloy layer 9 cformed within the thickness of a corresponding electrically conductivelayer 6 c; and a protruding portion 91 c protruding from the baseportion 90 c toward a corresponding solder bump 8 in the thicknessdirection D1 of the substrate 1. The protruding portion 91 c is locatedinside a corresponding opening 71 of the protective film 7. The outercircumferential shape of the protruding portion 91 c is the same orsubstantially the same as the outer circumferential shape of an endportion 81 c of the solder bump 8. The outer circumferential surface ofthe protruding portion 91 c is in contact with the inner circumferentialsurface of the opening 71 of the protective film 7. An extending portion900 c (a portion of the alloy layers 9 c) of the base portion 90 c thatsurrounds the protruding portion 91 c in a plan view in the thicknessdirection D1 of the substrate 1 is located between the protective film 7and the electrically conductive layer 6 c in the thickness direction D1of the substrate 1.

In the electronic component 100 c according to preferred embodiment 2,as in the electronic component 100 according to preferred embodiment 1,a surface 601 c of each electrically conductive layer 6 c that islocated on the protective film 7 side is in contact (close contact) withthe protective film 7 in a region between a corresponding alloy layer 9c and an edge 602 c on the connection electrode 5 side in a plan view inthe thickness direction D1, and therefore the moisture resistance can beimproved. In the electronic component 100 c according to preferredembodiment 2, as in the electronic component 100 according to preferredembodiment 1, the maximum height roughness of the surfaces 601 c of theelectrically conductive layers 6 c that are located on the protectivefilm 7 side is larger than the maximum height roughness of surfaces 901c of the alloy layers 9 c that are located on the protective film 7side. The maximum height roughness of the surfaces 601 c of theelectrically conductive layers 6 c that are located on the protectivefilm 7 side can be changed by subjecting the electrically conductivelayers 6 c to, for example, etching or a sandblast treatment in thecourse of production.

Preferred Embodiment 3

An electronic component 100 d according to preferred embodiment 3 of thepresent invention will be described referring to FIG. 10.

The electronic component 100 d according to preferred embodiment 3preferably includes a plurality of electrically conductive layers 6 dinstead of the plurality of electrically conductive layers 6 of theelectronic component 100 according to preferred embodiment 1 (see FIGS.1 and 2). Moreover, the electronic component 100 d according topreferred embodiment 3 preferably includes a cover portion 4 d, aplurality of connection electrodes 5 d, and a protective film 7 dinstead of the cover portion 4, the plurality of connection electrodes5, and the protective film 7, respectively, of the electronic component100 according to preferred embodiment 1. In the electronic component 100d according to preferred embodiment 3, the same elements and portions asthose in the electronic component 100 according to preferred embodiment1 are denoted by the same symbols, and their description will beomitted.

The cover portion 4 d includes a spacer layer 41 d and a cover layer 42d, as does the cover portion 4. The outer and inner circumferentialshapes of the spacer layer 41 d are the same or substantially the sameas the outer and inner circumferential shapes of the spacer layer 41.The outer circumferential shape of the cover layer 42 a is the same orsubstantially the same as the outer circumferential shape of the coverlayer 42. The material of the spacer layer 41 d and the material of thecover layer 42 d are preferably the same as the material of the spacerlayer 41 and the material of the cover layer 42, respectively.

The connection electrodes 5 d are on the wiring layers 3 and extend inthe thickness direction D1 of the substrate 1.

The electrically conductive layers 6 d are on the cover portion 4 d andon the connection electrode 5 a and are electrically connected to thewiring layers 3 via the connection electrodes 5 d.

Each electrically conductive layer 6 d preferably includes a first layer61, a second layer 62, and a third layer 63, as does the electricallyconductive layer 6 of the electronic component 100 according topreferred embodiment 1.

The material of the connection electrodes 5 d is the same as thematerial of the first layers 61 of the electrically conductive layers 6d. The connection electrodes 5 d are formed integrally with therespective first layers 61.

The protective film 7 d covers a surface 401 of the cover portion 4 dand also covers an outer circumferential surface 403 of the coverportion 4 d. The protective film 7 d covers the outer circumferentialsurface 403 of the cover portion 4 d so as to cover the connectionelectrodes 5 d provided on the outer circumferential surface 403 of thecover portion 4 d. The material of the protective film 7 d is the sameas the material of the protective film 7.

In the electronic component 100 d according to preferred embodiment 3,as in the electronic component 100 according to preferred embodiment 1,a surface 601 d of each electrically conductive layer 6 d that islocated on the protective film 7 side is in contact (close contact) withthe protective film 7 in a region between a corresponding alloy layer 9d and an edge 602 d on the connection electrodes 5 d side in a plan viewin the thickness direction D1, and therefore the moisture resistance canbe improved. Moreover, in the electronic component 100 d according topreferred embodiment 3, as in the electronic component 100 according topreferred embodiment 1, the maximum height roughness of the surfaces 601d of the electrically conductive layers 6 d that are located on theprotective film 7 side is larger than the maximum height roughness ofsurfaces 901 d the alloy layers 9 d that are located on the protectivefilm 7 side.

In the electronic component 100 d according to preferred embodiment 3,each connection electrode 5 d extends along one side surface of theouter circumferential surface 403 of the cover portion 4 d to acorresponding wiring layer 3 and connected to this wiring layer 3. Theprotective film 7 d covers the wiring layers 3. Therefore, in theelectronic component 100 d according to preferred embodiment 3, theflexibility in selection of the material of the substrate 1 is higherthan that when through electrodes are formed in the substrate 1.

Preferred Embodiment 4

An electronic component 100 e according to preferred embodiment 4 of thepresent invention will be described referring to FIG. 11.

The electronic component 100 e according to preferred embodiment 4preferably includes a substrate 1 e instead of the substrate 1 of theelectronic component 100 according to preferred embodiment 1 (see FIGS.1 and 2). Moreover, the electronic component 100 e according topreferred embodiment 4 preferably includes a cover portion 4 e, aplurality of connection electrodes 5 e, a plurality of electricallyconductive layers 6 e, and a protective film 7 e instead of the coverportion 4, the plurality of connection electrodes 5, the plurality ofelectrically conductive layers 6, and the protective film 7,respectively, of the electronic component 100 according to preferredembodiment 1. In the electronic component 100 e according to preferredembodiment 4, the same elements and portions as those in the electroniccomponent 100 according to preferred embodiment 1 are denoted by thesame symbols, and their description will be omitted.

The substrate le is a laminated substrate. The substrate le preferablyincludes a support substrate 14, a low-acoustic velocity film 15, and apiezoelectric thin film 16. The support substrate 14 supports amultilayer body including the low-acoustic velocity film 15 and thepiezoelectric thin film 16. The acoustic velocity of bulk wavespropagating through the support substrate is higher than the acousticvelocity of acoustic waves propagating through the piezoelectric thinfilm 16. The low-acoustic velocity film 15 is provided directly orindirectly on the support substrate 14. The acoustic velocity of bulkwaves propagating through the low-acoustic velocity film 15 is lowerthan the acoustic velocity of acoustic waves propagating through thepiezoelectric thin film 16. The piezoelectric thin film 16 is provideddirectly or indirectly on the low-acoustic velocity film 15. Thepiezoelectric thin film 16 is preferably made of, for example, LiTa03.The support substrate 14 is preferably, for example, a silicon film. Thelow-acoustic velocity film 15 is preferably, for example, a siliconoxide film.

The cover portion 4 e preferably includes a spacer layer 41 e and acover layer 42 e, as does the cover portion 4. The outer and innercircumferential shapes of the spacer layer 41 e are preferably the sameor substantially the same as the outer and inner circumferential shapesof the spacer layer 41. The outer circumferential shape of the coverlayer 42 e is preferably the same or substantially the same as the outercircumferential shape of the cover layer 42. The material of the spacerlayer 41 e and the material of the cover layer 42 e are preferably thesame as the material of the spacer layer 41 and the material of thecover layer 42, respectively.

The electronic component 100 e preferably includes a plurality of setsof the wiring layer 3, the connection electrode 5 e, the electricallyconductive layer 6 e, the solder bump 8, and an alloy layer 9 e. In eachof the plurality of sets, the connection electrode 5 e is on the wiringlayer 3 and extends in the thickness direction D1 of the substrate le.The connection electrode 5 e is a through electrode passing though thesubstrate le in the thickness direction D1 of the substrate 1 e. Thesubstrate le includes an electrically insulating film 19 thatelectrically insulates the support substrate 14 from the plurality ofconnection electrodes 5 e, the plurality of wiring layers 3, and theplurality of electrically conductive layers 6 e. In the electroniccomponent 100 e according to preferred embodiment 4, a portion of theelectrically insulating film 19 that is located below the piezoelectricthin film 16 also defines and functions as the low-acoustic velocityfilm 15. The low-acoustic velocity film 15 may be on the electricallyinsulating film 19. In the electronic component 100 e, the substrate lemay include, for example, a close contact layer interposed between thelow-acoustic velocity film 15 and the piezoelectric thin film 16. Inthis case, the adhesion between the low-acoustic velocity film 15 andthe piezoelectric thin film 16 can be improved. The close contact layeris preferably made of, for example, a resin (such as an epoxy resin or apolyimide resin), a metal, etc. In the electronic component 100 e, thesubstrate le may include, instead of the close contact layer, adielectric film between the low-acoustic velocity film 15 and thepiezoelectric thin film 16, on the piezoelectric thin film 16, or underthe low-acoustic velocity film 15.

Each electrically conductive layer 6 e includes a first layer 61, asecond layer 62, and a third layer 63, as do the electrically conductivelayers 6 of the electronic component 100 according to preferredembodiment 1 (see FIG. 1).

The protective film 7 e covers a back surface 12 e of the substrate leand the plurality of electrically conductive layers 6 e and includesopenings 71 in projection regions of a portion of the electricallyconductive layers 6 e in the thickness direction D1 of the substrate 1.

The electronic component 100 e according to preferred embodiment 4preferably includes the substrate le, the functional element portions 2,the wiring layers 3, the cover portion 4 e, the connection electrodes 5e, the electrically conductive layers 6 e, the protective film 7 e, thesolder bumps 8, and the alloy layers 9 e. The functional elementportions 2 are on the front surface 11 e side of the substrate le. Thewiring layers 3 are on the front surface 11 e side of the substrate leand electrically connected to the functional element portions 2. Thecover portion 4 e is on the front surface 11 e side of the substrate leand protects the functional element portions 2. The connectionelectrodes 5 e are on the wiring layers 3 and extend in the thicknessdirection D1 of the substrate 1 e. The electrically conductive layers 6e are on the back surface 12 e of the substrate 1 e that is opposite tothe front surface 11 e and on the connection electrodes 5 e and areelectrically connected to the wiring layers 3 via the connectionelectrodes 5 e. The protective film 7 e covers the back surface 12 e ofthe substrate 1 e and the electrically conductive layers 6 e andincludes the openings 71 in projection regions of a portion of theelectrically conductive layers 6 e in the thickness direction D1. Thesolder bumps 8 are electrically connected to the electrically conductivelayers 6 e via the openings 71. Each alloy layer 9 e is provided betweena corresponding solder bump 8 and a corresponding electricallyconductive layer 6 e in the thickness direction D1 to join the solderbump 8 to the electrically conductive layer 6 e. The alloy layers 9 epreferably differ in at least one of composition and a combination ofelements from the solder bumps 8. The electronic component 100 eaccording to preferred embodiment 4 includes a plurality of sets of thewiring layer 3, the connection electrode 5 e, the electricallyconductive layer 6 e, the solder bump 8, and the alloy layer 9 e. Theplurality of openings 71 corresponding to the plurality of sets areprovided in the protective film 7 e. In at least one set of theplurality of sets (preferably all the sets in this case), the connectionelectrode 5 e is disposed such that at least a portion thereof does notoverlap the solder bump 8 in a plan view in the thickness direction D1.The surface 601 e of the electrically conductive layer 6 e that islocated on the protective film 7 e side is in contact with theprotective film 7 e in a region between the alloy layer 9 e and an edge602 e on the connection electrode 5 e side in a plan view in thethickness direction D1.

In each of the plurality of sets in the electronic component 100 eaccording to preferred embodiment 4, as in the electronic component 100according to preferred embodiment 1, the surface 601 e of theelectrically conductive layer 6 e that is located on the protective film7 e side is in contact (e.g., in close contact) with the protective film7 in the region between the alloy layer 9 e and the edge 602 e on theconnection electrode 5 e side in a plan view in the thickness directionD1, and therefore the moisture resistance can be improved.

In each of the plurality of sets in the electronic component 100 eaccording to preferred embodiment 4, the connection electrode 5 e isspaced apart from the solder bump 8 in a plan view in the thicknessdirection D1. Therefore, in the electronic component 100 e according topreferred embodiment 4, the distance from the solder bump 8 to theconnection electrode 5 e is longer than that when the connectionelectrode 5 e includes a portion overlapping the solder bump 8 in a planview in the thickness direction D1. In this case, moisture from theoutside is unlikely to reach the connection electrode 5 e, and thereforethe moisture resistance can be improved.

In each of the plurality of sets in the electronic component 100 eaccording to preferred embodiment 4, the electrically conductive layer 6e surrounds the entire or substantially the entire circumference of thealloy layer 9 e. Therefore, in the electronic component 100 e accordingto preferred embodiment 4, the moisture resistance can be furtherimproved as compared with the case where the electrically conductivelayer 6 e does not surround the entire circumference of the alloy layer9 e.

In each of the plurality of sets in the electronic component 100 eaccording to preferred embodiment 4, at least a portion of the alloylayer 9 e is interposed between the protective film 7 e and theelectrically conductive layer 6 e (the second layer 62 thereof) in thethickness direction D1 of the substrate le. Therefore, in the electroniccomponent 100 e according to preferred embodiment 4, the joint strengthbetween the solder bump 8 and the electrically conductive layer 6 e canbe improved as compared with the case where at least a portion of thealloy layer 9 e is not interposed between the protective film 7 e andthe electrically conductive layer 6 e in the thickness direction D1 ofthe substrate 1 e.

In each of the plurality of sets in the electronic component 100 eaccording to preferred embodiment 4, the length L6 of a portion of theelectrically conductive layer 6 e that overlaps the protective film 7 ein the region between the alloy layer 9 e and the edge 602 e on theconnection electrode 5 e side in a plan view in the thickness direction(D1) is preferably larger than the length L9 of a portion of the alloylayer 9 e that overlaps the protective film 7 e. Therefore, in theelectronic component 100 e according to preferred embodiment 4, themoisture resistance can be further improved.

In each of the plurality of sets in the electronic component 100 eaccording to preferred embodiment 4, the electrically conductive layer 6e includes an Au layer (the third layer 63) that overlaps the protectivefilm 7 e in a plan view in the thickness direction D1. The Au layer (thethird layer 63) is connected to the alloy layer 9 e. The alloy layer 9 eincludes Au. Therefore, in the electronic component 100 e according topreferred embodiment 4, the weather resistance of the electricallyconductive layer 6 e and the alloy layer 9 e can be improved.

An electronic component 100 f according to a modification of preferredembodiment 4 will be described referring to 12A and 12B.

The electronic component 100 f according to the modification ofpreferred embodiment 4 preferably includes a plurality of electricallyconductive layers 6 f instead of the plurality of electricallyconductive layers 6 e of the electronic component 100 e according topreferred embodiment 4 (see FIG. 11). In the electronic component 100 faccording to the modification of preferred embodiment 4, the sameelements and portions as those in the electronic component 100 eaccording to preferred embodiment 4 are denoted by the same symbols, andtheir description will be omitted.

Each of the plurality of electrically conductive layers 6 f of theelectronic component 100 f preferably includes a first layer 61, asecond layer 62, and a third layer 63 and further includes a closecontact layer 64. The close contact layer 64 is interposed between thethird layer 63 and the protective film 7f. The close contact layer 64has higher adhesion to the protective film 7 f than the third layer 63.

In the electronic component 100 f, the protective film 7f preferablyincludes one material selected from the group consisting of an epoxyresin, a polyimide resin, and an acrylic resin, for example. The closecontact layer 64 preferably includes one material selected from thegroup consisting of Ti, Cr, and NiCr, for example.

In the electronic component 100 f according to the modification ofpreferred embodiment 4, as in the electronic component 100 e accordingto preferred embodiment 4, a surface 601 f of each of the electricallyconductive layers 6 f that is located on the protective film 7 f side isin contact (e.g., in close contact) with the protective film 7 f in aregion between a corresponding alloy layer 9 f and an edge 602 f on theconnection electrode 5 e side in a plan view in the thickness directionD1, and therefore the moisture resistance can be improved. In theelectronic component 100 f according to the modification of preferredembodiment 4, the electrically conductive layers 6 f include therespective close contact layer 64. Therefore, the adhesion between theprotective film 7 f and the surface 601 f of each electricallyconductive layer 6 f that is located on the protective film 7 f side inthe thickness direction D1 of the substrate le can be improved, so thatthe moisture resistance can be further improved. In the electroniccomponent 100 f according to the modification of preferred embodiment 4,as in the electronic component 100 e according to preferred embodiment4, the maximum height roughness of the surfaces 601 f of theelectrically conductive layers 6 f that are located on the protectivefilm 7 f side is larger than the maximum height roughness of surfaces901 f of alloy layers 9 f that are located on the protective film 7 fside.

Preferred Embodiment 5

An electronic component 100 g according to preferred embodiment 5 of thepresent invention will be described referring to FIG. 13.

The electronic component 100 g according to preferred embodiment 5preferably includes a plurality of electrically conductive layers 6 ginstead of the plurality of electrically conductive layers 6 e of theelectronic component 100 e according to preferred embodiment 4 (see FIG.11). In the electronic component 100 g according to preferred embodiment5, the same elements and portions as those in the electronic component100 e according to preferred embodiment 4 are denoted by the samesymbols, and their description will be omitted.

Each of the plurality of electrically conductive layers 6 g preferablyincludes Cu, for example. More particularly, each of the plurality ofelectrically conductive layers 6 g is preferably a Cu layer, forexample. Specifically, although the electrically conductive layers 6 eof the electronic component 100 e according to preferred embodiment 4each have a multilayer structure, the electrically conductive layers 6 gin preferred embodiment 5 each have a single layer structure. Theelectrically conductive layers 6 g preferably includes Cu as a basematerial, and any impurities may be added, for example.

The electronic component 100 g according to preferred embodiment 5includes a plurality of sets of the wiring layer 3, a connectionelectrode 5 e, the electrically conductive layer 6 g, the solder bump 8,and an alloy layer 9 g. In each of the plurality of sets, theelectrically conductive layer 6 g is joined to the solder bump 8 via thealloy layer 9 g. The alloy layers 9 g include Sn and Cu as elements. Thealloy layers 9 g differ in at least composition from the solder bumps 8.Each alloy layer 9 g is formed by the reaction between a Cu layer thatlater becomes a corresponding electrically conductive layer 6 g andmelted solder (hereinafter referred to as “molten solder”) melted duringreflow treatment in the course of production of the electronic component100 g. More particularly, each alloy layer 9 g is formed by the reactionbetween the molten solder and the Cu layer (electrically conductivelayer) formed before the reflow treatment.

The alloy layers 9 g are provided in the electrically conductive layers6 g so as to extend to intermediate positions in the thickness directionand do not pass through the electrically conductive layers 6 g. Thealloy layers 9 g are connected to the electrically conductive layers 6 gin in-plane directions orthogonal to the thickness direction D1 of thesubstrate 1 e. The alloy layers 9 g are connected, in the thicknessdirection D1 of the substrate le, to the solder bumps 8 and portions ofthe electrically conductive layers 6 g that are located directly belowthe alloy layers 9 g.

The alloy layers 9 g are larger than the openings 71 in a plan view inthe thickness direction D1 of the substrate 1 e. A portion of each alloylayer 9 g is located between the protective film 7 g and a correspondingelectrically conductive layer 6 g in the thickness direction D1 of thesubstrate 1 e. In the electronic component 100 g, the protective film 7g preferably includes one material selected from the group consisting ofan epoxy resin, a polyimide resin, and an acrylic resin, for example.

In each of the plurality of sets in the electronic component 100 gaccording to preferred embodiment 5, as in the electronic component 100e according to preferred embodiment 4, a surface 601 g of theelectrically conductive layer 6 g that is located on the protective film7 g side is in contact (close contact) with the protective film 7 g in aregion between the alloy layer 9 g and an edge 602 g on the connectionelectrode 5 e side in a plan view in the thickness direction D1, andtherefore the moisture resistance can be improved. Moreover, in each ofthe plurality of sets in the electronic component 100 g according topreferred embodiment 5, as in the electronic component 100 e accordingto preferred embodiment 4, the maximum height roughness of the surface601 g of the electrically conductive layer 6 g that is located on theprotective film 7 g side is larger than the maximum height roughness ofa surface 901 g of the alloy layer 9 g that is located on the protectivefilm 7 g side. The maximum height roughness of the surface 601 g of theelectrically conductive layer 6 g that is located on the protective film7 g side can be changed by subjecting the electrically conductive layer6 g to etching or sandblast treatment in the course of production.

Preferred Embodiment 6

An electronic component 100 h according to preferred embodiment 6 of thepresent invention will be described referring to FIG. 14.

The electronic component 100 h according to preferred embodiment 6preferably includes a cover portion 4 h, a plurality of connectionelectrodes 5 h, a plurality of electrically conductive layers 6 h, and aprotective film 7 h instead of the cover portion 4, the plurality ofconnection electrodes 5, the plurality of electrically conductive layers6, and the protective film 7, respectively, of the electronic component100 according to preferred embodiment 1 (see FIGS. 1 and 2). In theelectronic component 100 h according to preferred embodiment, the sameelements and portions as those in the electronic component 100 accordingto preferred embodiment 1 are denoted by the same symbols, and theirdescription will be omitted.

The cover portion 4 h preferably includes a spacer layer 41 h and acover layer 42 h, as does the cover portion 4. The outer and innercircumferential shapes of the spacer layer 41 h are preferably the sameor substantially the same as the outer and inner circumferential shapesof the spacer layer 41. The outer circumferential shape of the coverlayer 42 h is preferably the same or substantially the same as the outercircumferential shape of the cover layer 42. The material of the spacerlayer 41 h and the material of the cover layer 42 h are the same as thematerial of the spacer layer 41 and the material of the cover layer 42,respectively.

The electronic component 100 h according to preferred embodiment 6preferably includes a plurality of sets of the wiring layer 3, theconnection electrode 5 h, the electrically conductive layer 6 h, thesolder bump 8, and an alloy layer 9 h. In each of the plurality of sets,the connection electrode 5 h is on the wiring layer 3 and extends in thethickness direction D1 of the substrate 1. In this case, the connectionelectrode 5 h extends from the electrically conductive layer 6 h sidealong one side surface of the outer circumferential surface 13 to thefront surface 11 of the substrate 1 and is connected to the wiring layer3. The connection electrode 5 h include a portion provided along the oneside surface of the outer circumferential surface 13 of the substrate 1;and a portion provided along the front surface 11 of the substrate 1.

Each of the electrically conductive layers 6 h preferably includes afirst layer 61, a second layer 62, and a third layer 63, as do theelectrically conductive layers 6 of the electronic component 100according to preferred embodiment 1.

The protective film 7 h covers a back surface 12 e of the substrate 1,the outer circumferential surface 13 of the substrate 1, a portion ofthe front surface 11 of the substrate 1 that is located outward of thecover portion 4 h, the electrically conductive layers 6 h, etc. andincludes openings 71 in projection regions of a portion of theelectrically conductive layers 6 h in the thickness direction D1.

The electronic component 100 h according to preferred embodiment 6preferably includes the substrate 1, the functional element portions 2,the wiring layers 3, the cover portion 4 h, the connection electrodes 5h, the electrically conductive layers 6 h, the protective film 7h, thesolder bumps 8, and alloy layers 9 h. The functional element portions 2are on the front surface 11 side of the substrate 1. The wiring layers 3are on the front surface 11 side of the substrate 1 and are electricallyconnected to the functional element portions 2. The cover portion 4 h ison the front surface 11 side of the substrate 1 and protects thefunctional element portions 2. The connection electrodes 5 h are on thewiring layers 3 and extend in the thickness direction D1 of thesubstrate 1. The electrically conductive layers 6 h are on theconnection electrodes 5 h and on the back surface 12 of the substrate 1that is opposite to the front surface 11 and electrically connected tothe wiring layers 3 via the connection electrodes 5h. The protectivefilm 7 h covers the back surface 12 of the substrate 1 and theelectrically conductive layers 6 h and includes the openings 71 in theprojection regions of a portion of the electrically conductive layers 6h in the thickness direction D1. The solder bumps 8 are electricallyconnected to the electrically conductive layers 6 h via the openings 71.The alloy layers 9 h are provided between the solder bumps 8 and theelectrically conductive layers 6 h in the thickness direction D1 to jointhe solder bumps 8 to the electrically conductive layers 6 h. The alloylayers 9 h differ in at least one of composition and a combination ofelements from the solder bumps 8. The electronic component 100 haccording to preferred embodiment 6 includes a plurality of sets of thewiring layer 3, the connection electrode 5 h, the electricallyconductive layer 6 h, the solder bump 8, and the alloy layer 9 h. Theprotective film 7 h includes the plurality of openings 71 correspondingto the plurality of sets. In at least one set of the plurality of sets(all the sets in this case), the connection electrode 5 h is structuredsuch that at least a portion thereof does not overlap the solder bump 8in a plan view in the thickness direction D1. A surface 601 h of theelectrically conductive layer 6 h that is located on the protective film7 h side is in contact with the protective film 7 h in a region betweenthe alloy layer 9 h and an edge 602 h on the connection electrode 5 hside in a plan view in the thickness direction D1.

In each of the plurality of sets in the electronic component 100 haccording to preferred embodiment 6, as in the electronic component 100according to preferred embodiment 1, the surface 601 h of theelectrically conductive layer 6 h that is located on the protective film7 h side is in contact (e.g., in close contact) with the protective film7 h in the region between the alloy layer 9 h and the edge 602 h on theconnection electrode 5 h side in a plan view in the thickness directionD1, and therefore the moisture resistance can be improved.

In each of the plurality of sets in the electronic component 100 haccording to preferred embodiment 6, the connection electrode 5 h ispreferably spaced apart from the solder bump 8 in a plan view in thethickness direction D1 of the substrate 1. Therefore, in the electroniccomponent 100 h according to preferred embodiment 6, the distance fromthe solder bump 8 to the connection electrode 5 h is preferably longerthan that when the connection electrode 5 h includes a portionoverlapping the solder bump 8 in a plan view in the thickness directionD2. In this case, moisture from the outside is unlikely to reach theconnection electrode 5 h, and therefore the moisture resistance can beimproved.

In each of the plurality of sets in the electronic component 100 haccording to preferred embodiment 6, the connection electrode 5 hextends along the outer circumferential surface 13 of the substrate 1 tothe front surface 11 of the substrate 1 and is connected to the wiringlayer 3. Therefore, in the electronic component 100 h according topreferred embodiment 6, the flexibility in selection of the material ofthe substrate 1 is higher than that when through electrodes are providedin the substrate 1.

Preferred Embodiment 7

An electronic component 100 i according to preferred embodiment 7 of thepresent invention will be described referring to FIG. 15.

In the electronic component 100 i according to preferred embodiment 7,one of the plurality of (four, for example) connection electrodes 5 ofthe electronic component 100 according to preferred embodiment 1 (seeFIGS. 1 and 2) (i.e., the left connection electrode 5 in FIG. 15) ispreferably structured to entirely or substantially entirely overlap oneof the solder bumps 8 in a plan view in the thickness direction D1 ofthe substrate 1. In the electronic component 100 i according topreferred embodiment 7, the same elements and portions as those in theelectronic component 100 according to preferred embodiment 1 are denotedby the same symbols, and their description will be appropriatelyomitted.

The electronic component 100 i according to preferred embodiment 7preferably includes a plurality of sets of the wiring layer 3, theconnection electrode 5, the electrically conductive layer 6, the solderbump 8, and the alloy layer 9, as does the electronic component 100according to preferred embodiment 1. The protective film 7 includes aplurality of openings 71 corresponding to the plurality of sets.

In at least one (preferably, for example, three in this case) of theplurality of (preferably, for example, four in this case) sets in theelectronic component 100 i according to preferred embodiment 7, theconnection electrode 5 is structured such that at least a portionthereof does not overlap the solder bump 8 in a plan view in thethickness direction D1. The surface 601 of the electrically conductivelayer 6 that is located on the protective film 7 side is preferably incontact with the protective film 7 in a region between the alloy layer 9and the edge 602 on the connection electrode 5 side in a plan view inthe thickness direction D1. In the electronic component 100 i accordingto preferred embodiment 7, in the rest of the plurality of setsdifferent from the at least one set (the remaining one set in thiscase), the connection electrode 5 is disposed so as to entirely orsubstantially entirely overlap one of the solder bumps 8 in a plan viewin the thickness direction D1.

In each of the plurality of sets in the electronic component 100 iaccording to preferred embodiment 7, as in the electronic component 100according to preferred embodiment 1, the surface 601 of the electricallyconductive layer 6 that is located on the protective film 7 side is incontact (e.g., in close contact) with the protective film 7 in a regionbetween the alloy layer 9 and the edge 602 on the connection electrode 5side in a plan view in the thickness direction D1. Therefore, even whenmoisture passes through a gap between the alloy layer 9 and theprotective film 7, the moisture is unlikely to reach the connectionelectrode 5, so that the moisture is unlikely to reach the functionalelement portions 2. Therefore, in the electronic component 100 iaccording to preferred embodiment 7, the moisture resistance can beimproved, and the reliability can be improved.

In the electronic component 100 i according to preferred embodiment 7,as in the electronic component 100 according to preferred embodiment 1,the cover portion 4 preferably includes a cover layer 42 and a spacerlayer 41 and may further include one or a plurality of intermediatesupport layers (second spacer layers) disposed inward of the spacerlayer 41 (first spacer layer) and located between the cover layer 42 andthe substrate 1. In this case, the plurality of connection electrodes 5passing through the cover portion 4 may include a through electrodepassing through the cover layer 42 and the spacer layer 41 and a throughelectrode passing through the cover layer 42 and the second spacerlayers.

The arrangement of the plurality of connection electrodes 5 in theelectronic component 100 i according to preferred embodiment 7 isapplicable to modifications 1 and 2 of preferred embodiment 1 andpreferred embodiments 2 and 3.

Preferred Embodiment 8

An electronic component 100 j according to preferred embodiment 8 of thepresent invention will be described referring to FIG. 16.

In the electronic component 100 j according to preferred embodiment 8,one of the plurality of (four, for example) connection electrodes 5 ofthe electronic component 100 e (see FIG. 11) according to preferredembodiment 4 (i.e., the left connection electrode 5 e in FIG. 16) ispreferably structured to entirely or substantially entirely overlap oneof the solder bumps 8 in a plan view in the thickness direction D1 ofthe substrate 1 e. In the electronic component 100 j according topreferred embodiment 8, the same elements and portions as those in theelectronic component 100 e according to preferred embodiment 4 aredenoted by the same symbols, and their description will be omitted.

The electronic component 100 j according to preferred embodiment 8preferably includes a plurality of sets of the wiring layer 3, theconnection electrode 5 e, the electrically conductive layer 6 e, thesolder bump 8, and the alloy layer 9 e, as does the electronic component100 e according to preferred embodiment 4. The protective film 7 eincludes a plurality of openings 71 corresponding to the plurality ofsets. In at least one (preferably, for example , three in this case) ofthe plurality of (preferably, for example, four in this case) sets, theconnection electrode 5 e is disposed such that at least a portionthereof does not overlap the solder bump 8 in a plan view in thethickness direction D1. The surface 601 e of the electrically conductivelayer 6 e that is located on the protective film 7 e side is in contactwith the protective film 7 e in a region between the alloy layer 9 e andthe edge 602 e on the connection electrode 5 e side in a plan view inthe thickness direction D1. In the electronic component 100 j accordingto preferred embodiment 8, in the rest of the plurality of setsdifferent from the at least one set (the remaining one set in thiscase), the connection electrode 5 e is structured to entirely orsubstantially entirely overlap one of the solder bumps 8 in a plan viewin the thickness direction D1.

In each of the plurality of sets in the electronic component 100 jaccording to preferred embodiment 8, as in the electronic component 100e according to preferred embodiment 4, the surface 601 e of theelectrically conductive layer 6 e that is located on the protective film7 e side is in contact (close contact) with the protective film 7 e in aregion between the alloy layer 9 e and the edge 602 e on the connectionelectrode 5 e side in a plan view in the thickness direction D1, so thatthe moisture resistance can be improved.

The arrangement of the plurality of connection electrodes 5 e in theelectronic component 100 j according to preferred embodiment 8 isapplicable to modifications 1 and 2 of preferred embodiment 1 andpreferred embodiments 4 and 5.

Preferred embodiments 1 to 8 described above are merely examples ofvarious preferred embodiments of the present invention. Variousmodifications can be made to the design etc. of preferred embodiments 1to 8 as long as the advantageous effects of the present invention can beachieved.

It is only necessary that the electronic components 100, 100 a, 100 b,100 c, 100 d, 100 h, and 100 i have piezoelectricity in at least regionsin which the IDT electrodes 21 are provided. The electronic components100, 100 a, 100 b, 100 c, 100 d, 100 h, and 100 i are not limited to thepiezoelectric substrates and may each be a laminated substrate if sodesired.

The laminated substrate preferably includes, for example, ahigh-acoustic velocity support substrate, a low-acoustic velocity film,and a piezoelectric thin film. The high-acoustic velocity supportsubstrate supports a multilayer body including the low-acoustic velocityfilm and the piezoelectric thin film. The acoustic velocity of bulkwaves propagating through the high-acoustic velocity support substrateis higher than the acoustic velocity of acoustic waves propagatingthrough the piezoelectric thin film. The low-acoustic velocity film isprovided directly or indirectly on the high-acoustic velocity supportsubstrate. The acoustic velocity of bulk waves propagating through thelow-acoustic velocity film is lower than the acoustic velocity of bulkwaves propagating through the piezoelectric thin film. The piezoelectricthin film is disposed directly or indirectly on the low-acousticvelocity film. The piezoelectric thin film is preferably made of, forexample, LiTaO₃ (lithium tantalate), LiNbO₃ (lithium niobate), ZnO (zincoxide), AIN (aluminum nitride), or PZT (lead zirconate titanate). Thehigh-acoustic velocity support substrate preferably includes, forexample, at least one material selected from the group consisting ofsilicon, aluminum nitride, aluminum oxide, silicon carbide, siliconnitride, sapphire, lithium tantalate, lithium niobate, quartz, alumina,zirconia, cordierite, mullite, steatite, forsterite, magnesia, anddiamond. The low-acoustic velocity film preferably includes, forexample, at least one material selected from the group consisting ofsilicon oxide, glass, silicon oxynitride, tantalum oxide, and a compoundobtained by adding fluorine or boron to silicon oxide.

The laminated substrate is not limited to the structure including thehigh-acoustic velocity support substrate, the low-acoustic velocityfilm, and the piezoelectric thin film. For example, the laminatedsubstrate may be a substrate including a support substrate, ahigh-acoustic velocity film, a low-acoustic velocity film, and apiezoelectric thin film.

The support substrate preferably includes, for example, at least onematerial selected from the group consisting of sapphire, piezoelectricmaterials such as lithium tantalate, lithium niobate, and quartz,ceramics such as alumina, magnesia, silicon nitride, aluminum nitride,silicon carbide, zirconia, cordierite, mullite, steatite, andforsterite, glass, silicon, gallium nitride, and resins.

The high-acoustic velocity film preferably includes, for example, onematerial selected from the group consisting of diamond-like carbon,aluminum nitride, aluminum oxide, silicon carbide, silicon nitride,silicon, sapphire, piezoelectric materials such as lithium tantalate,lithium niobate, and quartz, ceramics such as alumina, zirconia,cordierite, mullite, steatite, and forsterite, magnesia, and diamond.

The high-acoustic velocity film functions such that acoustic waves areconfined in a portion in which the piezoelectric thin film and thelow-acoustic velocity film are laminated and are prevented from leakingto the structure below the high-acoustic velocity film. In a structureincluding the laminated substrate including the high-acoustic velocityfilm, the energy of acoustic waves in specific modes used to obtainfilter or resonator characteristics is distributed over the entire orsubstantially the entire piezoelectric thin film and the entire orsubstantially the entire low-acoustic velocity film and also distributedon part of the high-acoustic velocity film that is located on thelow-acoustic velocity film side, but is not distributed in the supportsubstrate.

When the substrate 1 is the laminated substrate, it is preferable that afunctional film including the piezoelectric thin film laminated directlyor indirectly to the high-acoustic velocity support substrate or thesupport substrate is spaced apart from the outer circumference of thesurface of the high-acoustic velocity support substrate or the supportsubstrate in a plan view in the thickness direction D1 of the substrate1. When the substrate 1 is the laminated substrate, the electroniccomponent may include an electrically insulating layer that is providedon the surface of the high-acoustic velocity support substrate or thesupport substrate and surrounds the functional film. In this case, thesecond connection portions 32 of the wiring layers 3 may be provided onthe electrically insulating layer. The material of the electricallyinsulating layer is preferably, for example, a synthetic resin such asan epoxy resin or a polyimide resin.

The substrate 1 may include, instead of the low-acoustic velocity film,an acoustic impedance layer between the piezoelectric thin film and thesupport substrate. The acoustic impedance layer has the function ofpreventing acoustic waves excited by the IDT electrodes 21 from leakingto the support substrate. The acoustic impedance layer preferablyincludes a multilayer structure in which at least one high-acousticimpedance layer having a relatively high acoustic impedance and at leastone low-acoustic impedance layer having a relatively low acousticimpedance are arranged in the thickness direction of the supportsubstrate. In the above multilayer structure, a plurality of thehigh-acoustic impedance layers may be provided, and a plurality of thelow-acoustic impedance layers may be provided. In this case, themultilayer structure is a structure in which the plurality ofhigh-acoustic impedance layers and the plurality of low-acousticimpedance layers are arranged alternately in the thickness direction ofthe support substrate.

Each high-acoustic impedance layer is preferably made of, for example,platinum, tungsten, aluminum nitride, lithium tantalate, sapphire,lithium niobate, silicon nitride, or zinc oxide.

Each low-acoustic impedance layer is preferably made of, for example,silicon oxide, aluminum, or titanium.

In the electronic component 100, for example, a plurality of surfaceacoustic wave resonators each including a plurality of IDT electrodes 21may be electrically connected to each other to define a bandpass filter.The number of wiring layers 3, the number of connection electrodes 5,the number of electrically conductive layers 6, the number of alloylayers 9, and the number of solder bumps 8 are not limited to 4 and maybe or a plural number other than 4. These numbers are also applicable tothe electronic components 100 a, 100 b, 100 c, 100 d, 100 e, 100 f, 100g, 100 h, 100 i, and 100 j.

The material of the spacer layer 41, the material of the cover layer 42,and the material of the protective film 7 in the electronic components100, 100 a, 100 b, 100 c, and 100 i are not limited to organicmaterials, such as synthetic resins, and may be inorganic materials.

Each of the electronic components 100, 100 a, 100 b, 100 c, 100 d, and100 i may include a protective insulating layer that covers thefunctional element portions 2 and a portion of the second connectionportions 32 of the wiring layers 3 on the front surface 11 side of thesubstrate 1. The material of the protective insulating layer ispreferably, for example, silicon oxide, silicon nitride, diamond-likecarbon, etc. The thickness of the protective insulating layer ispreferably, for example, several tens of nanometers.

The electrically conductive layers 6 and 6 a may each include a Pd layerinterposed between the second layer (Ni layer) 62 and the third layer(Au layer) 63. The first layer 61 is not limited to the Cu layer and maybe a Cr layer.

In the electrically conductive layers 6 and 6 b, for example, theintermediate portion 66 may include a spiral or meandering inductor.

The electronic component is not limited to the acoustic wave device andmay be, for example, a semiconductor device. In the electroniccomponent, when each functional element portion does not include the IDTelectrode but is a semiconductor element, the cover portion does notnecessarily have the structure including the spacer layer and the coverlayer and may have a single layer structure. The cover portion may be amultilayer body having three or more layers. In this case, the coverportion may be in contact with the semiconductor element. Thesemiconductor element is preferably, for example, a transistor, a diode,a capacitor, etc.

(Summary)

In accordance with the above-described preferred embodiments 1 to 8etc., the following aspects are disclosed.

An electronic component (100; 100 a; 100 b; 100 c; 100 d; 100 i)according to a preferred embodiment includes a substrate (1); afunctional element portion (2), a wiring layer (3), a cover portion (4;4 a; 4 d), a connection electrode (5; 5 a; 5 d), an electricallyconductive layer (6; 6 a; 6 b; 6 c; 6 d), a protective film (7; 7 d), asolder bump (8), and an alloy layer (9; 9 a; 9 b; 9 c; 9 d). Thefunctional element portion (2) is on a front surface (11) side of thesubstrate (1). The wiring layer (3) is on the front surface (11) side ofthe substrate (1) and is electrically connected to the functionalelement portion (2). The cover portion (4; 4 a; 4 d) is on the frontsurface (11) side of the substrate (1) and protects the functionalelement portion (2). The connection electrode (5; 5 a; 5 d) is on thewiring layer (3) and extends in a thickness direction (D1) of thesubstrate (1). The electrically conductive layer (6; 6 a; 6 b; 6 c; 6 d)is on the cover portion (4; 4 a; 4 d) and the connection electrode (5; 5a; 5 d) and electrically connected to the wiring layer (3) via theconnection electrode (5; 5 a; 5 d). The protective film (7; 7 d) coversthe cover portion (4; 4 a; 4 d) and the electrically conductive layer(6; 6 a; 6 b; 6 c; 6 d) and has an opening (71) in a projection regionof part of the electrically conductive layer (6; 6 a; 6 b; 6 c; 6 d) inthe thickness direction (D1). The solder bump (8) is electricallyconnected to the electrically conductive layer (6; 6 a; 6 b; 6 c; 6 d)via the opening (71). The alloy layer (9; 9 a; 9 b; 9 c; 9 d) is formedbetween the solder bump (8) and the electrically conductive layer (6; 6a; 6 b; 6 c; 6 d) in the thickness direction (D1) to join the solderbump (8) to the electrically conductive layer (6; 6 a; 6 b; 6 c; 6 d)and differs in at least one of composition and a combination of elementsfrom the solder bump (8). The electronic component (100; 100 a; 100 b;100 c; 100 d; 100 i) includes a plurality of sets of the wiring layer(3), the connection electrode (5; 5 a; 5 d), the electrically conductivelayer (6; 6 a; 6 b; 6 c; 6 d), the solder bump (8), and the alloy layer(9; 9 a; 9 b; 9 c; 9 d). The protective film (7; 7 d) has a plurality ofthe openings (71) corresponding to the plurality of sets. In at leastone set of the plurality of sets, the connection electrode (5; 5 a; 5 d)is disposed such that at least a portion thereof does not overlap thesolder bump (8) in a plan view in the thickness direction (D1). Theelectrically conductive layer (6; 6 a; 6 b; 6 c; 6 d) is in contact withthe protective film (7; 7 d) in a region between the alloy layer (9; 9a; 9 b; 9 c; 9 d) and an edge (602; 602 a; 602 b; 602 c; 602 d) of theelectrically conductive layer (6; 6 a; 6 b; 6 c; 6 d) that is located ona connection electrode (5; 5 a; 5 d) side in a plan view in thethickness direction (D1).

In the above-described electronic component (100; 100 a; 100 b; 100 c;100 d; 100 i), the moisture resistance can be improved.

In an electronic component (100; 100 a; 100 b; 100 c; 100 d; 100 i)according to a preferred embodiment, in a set different from the atleast one set of the plurality of sets, the connection electrode (5) isdisposed so as to entirely or substantially entirely overlap the solderbump (8) in a plan view in the thickness direction (D1).

In an electronic component (100; 100 a; 100 b; 100 c; 100 d; 100 i)according to a preferred embodiment, in the at least one set, theconnection electrode (5; 5 d) is spaced apart from the solder bump (8)in a plan view in the thickness direction (D1).

In an electronic component (100; 100 a; 100 b; 100 c; 100 d; 100 i)according to a preferred embodiment, in the connection electrode (5; 5d) in each of the plurality of sets, the distance from the solder bump(8) to the connection electrode (5; 5 d) is longer than that when theconnection electrode (5; 5 d) has a portion overlapping the solder bump(8) in a plan view in the thickness direction (D1). Therefore, moisturefrom the outside is unlikely to reach the connection electrode (5; 5 d),so that the moisture resistance can be improved.

In an electronic component (100; 100 a; 100 b; 100 c; 100 d; 100 i)according to a preferred embodiment, in each of the plurality of sets,the electrically conductive layer (6; 6 a; 6 b; 6 c; 6 d) surrounds theentire or substantially the entire circumference of the alloy layer (9;9 a; 9 b; 9 c; 9 d).

In the above-described electronic component (100; 100 a; 100 b; 100 c;100 d; 100 i), the moisture resistance can be further improved ascompared with the case where the electrically conductive layer (6; 6 a;6 b; 6 c; 6 d) in each of the plurality of sets does not surround theentire circumference of the alloy layer (9; 9 a; 9 b; 9 c; 9 d).

In an electronic component (100; 100 a; 100 b; 100 c; 100 d; 100 i)according to a preferred embodiment, in each of the plurality of sets,at least a portion of the alloy layer (9; 9 a; 9 b; 9 c; 9 d) isinterposed between the protective film (7; 7 d) and the electricallyconductive layer (6; 6 a; 6 b; 6 c; 6 d) in the thickness direction(D1).

In the above-described electronic component (100; 100 a; 100 b; 100 c;100 d; 100 i), the joint strength between the solder bump (8) and theelectrically conductive layer (6; 6 a; 6 b; 6 c; 6 d) can be improved ascompared with the case where at least a portion of the alloy layer (9; 9a; 9 b; 9 c; 9 d) in each of the plurality of sets is not interposedbetween the protective film (7; 7 d) and the electrically conductivelayer (6; 6 a; 6 b; 6 c; 6 d) in the thickness direction (D1) of thesubstrate (1).

In an electronic component (100; 100 a; 100 b; 100 c; 100 d; 100 i)according to a preferred embodiment, in the at least one set, the length(L6) of a portion of the electrically conductive layer (6; 6 a; 6 b; 6c; 6 d) that overlaps the protective film (7; 7 d) in a region betweenthe alloy layer (9; 9 a; 9 b; 9 c; 9 d) and the edge (602; 602 a; 602 b;602 c; 602 d) of the electrically conductive layer (6; 6 a; 6 b; 6 c; 6d) that is located on the connection electrode (5; 5 a; 5 d) side in aplan view in the thickness direction (D1) is larger than the length (L9)of a portion of the alloy layer (9; 9 a; 9 b; 9 c; 9 d) that overlapsthe protective film (7; 7 d).

In the above-described electronic component (100; 100 a; 100 b; 100 c;100 d; 100 i), the moisture resistance can be further improved.

In an electronic component (100; 100 a; 100 b; 100 d; 100 i) accordingto a preferred embodiment, in each of the plurality of sets, theelectrically conductive layer (6; 6 a; 6 b; 6 d) includes a Au layer(the third layer 63) overlapping the protective film (7) in a plan viewin the thickness direction (D1). The Au layer (the third layer 63) isconnected to the alloy layer (9; 9 a; 9 b; 9 d). The alloy layer (9; 9a; 9 b; 9 d) includes Au.

In the above-described electronic component (100; 100 a; 100 b; 100 d;100 i), the weather resistance of the electrically conductive layer (6;6 a; 6 b; 6 d) and the alloy layer (9; 9 a; 9 b; 9 d) in each of theplurality of sets can be improved.

In an electronic component (100 b) according to a preferred embodiment,in each of the plurality of sets, the electrically conductive layer (6b) includes a close contact layer (64). The close contact layer (64) isinterposed between the Au layer (the third layer 63) and the protectivefilm (7). The close contact layer (64) has higher adhesion to theprotective film (7) than the Au layer (the third layer 63).

In the above-described electronic component (100 b), the electricallyconductive layer (6 b) in each of the plurality of sets includes theclose contact layer (64). Therefore, the adhesion between the protectivefilm (7) and the surface (601 b) of the electrically conductive layer (6b) that is located on the protective film (7) side in the thicknessdirection (D1) of the substrate (1) can be improved, so that themoisture resistance can be further improved.

In an electronic component (100 b) according to a preferred embodiment,the protective film (7) includes one material selected from the groupconsisting of an epoxy resin, a polyimide resin, and an acrylic resin.The close contact layer (64) includes one material selected from thegroup consisting of Ti, Cr, and NiCr.

In the above-described electronic component (100 b), the close contactlayer (64) can be formed by, for example, sputtering or vapordeposition.

In an electronic component (100 c) according to a preferred of thepresent invention, in each of the plurality of sets, the conductivelayer (6 c) includes Cu.

In the above-described electronic component (100 c) according to thetenth aspect, it is possible to reduce the resistance of the conductivelayer (6 c).

In an electronic component (100; 100 a; 100 b; 100 c; 100 d; 100 i)according to a preferred embodiment, in the at least one set, themaximum height roughness of a surface (601; 601 a; 601 b; 601 c) of theelectrically conductive layer (6; 6 a; 6 b; 6 c; 6 d) that is located ona protective film (7; 7 d) side is larger than the maximum heightroughness of a surface (901; 901 a; 901 b; 901 c; 901 d) of the alloylayer (9; 9 a; 9 b; 9 c; 9 d) that is located on the protective film (7;7 d) side.

In the above-described electronic component according to the eleventhaspect (100; 100 a; 100 b; 100 c; 100 d; 100 i), the moisture resistancecan be improved as compared with the case where the maximum heightroughness of the surface (601; 601 a; 601 b; 601 c; 601 d) of theelectrically conductive layer (6; 6 a; 6 b; 6 c; 6 d) that is located onthe protective film (7; 7 d) side is equal to or lower than the maximumheight roughness of the surface (901; 901 a; 901 b; 901 c; 901 d) of thealloy layer (9; 9 a; 9 b; 9 c; 9 d) that is located on the protectivefilm (7; 7 d) side.

In an electronic component (100; 100 a; 100 b; 100 c; 100 d; 100 i)according to a preferred embodiment, in the at least one set, themaximum height roughness of the surface (601; 601 a; 601 b; 601 c; 601d) of the electrically conductive layer (6; 6 a; 6 b; 6 c; 6 d) that islocated on the protective film (7; 7 d) side is 1μm or more.

In the above-described electronic component (100; 100 a; 100 b; 100 c;100 d; 100 i), the moisture resistance can be improved as compared withthe case where the maximum height roughness of the surface (601; 601 a;601 b; 601 c; 601 d) of the electrically conductive layer (6; 6 a; 6 b;6 c; 6 d) that is located on the protective film (7; 7 d) side is lessthan 1 μm.

In an electronic component (100; 100 a; 100 b; 100 c; 100 d; 100 i)according to a preferred embodiment, in each of the plurality of sets,the solder bump (8) overlaps the entire or substantially the entireopening (71) in a plan view in the thickness direction (D1).

In the above-described electronic component (100; 100 a; 100 b; 100 c;100 d; 100 i), in the each of the plurality of sets, the joint strengthbetween the solder bump (8) and the electrically conductive layer (6; 6a; 6 b; 6 c; 6 d) can be improved.

In an electronic component (100; 100 a; 100 b; 100 c; 100 i) accordingto a preferred embodiment, in each of the plurality of sets, theconnection electrode (5; 5 a) is a through electrode passing through thecover portion (4) in the thickness direction (D1) of the substrate (1).

The above-described electronic component (100; 100 a; 100 b; 100 c; 100i) can be reduced in size.

In an electronic component (100; 100 a; 100 b; 100 c; 100 i) accordingto a preferred embodiment, the functional element portion (2) includesan IDT electrode (21). The substrate (1) has piezoelectricity at leastin a region in which the IDT electrode (21) is disposed. The coverportion (4; 4 a) includes a cover layer (42; 42 a) and a spacer layer(41; 41 a). The cover layer (42; 42 a) faces the substrate (1) in thethickness direction (D1) and is spaced apart from the functional elementportion (2). The spacer layer (41; 41 a) has a frame shape. The spacerlayer (41; 41 a) is interposed between the substrate (1) and the coverlayer (42; 42 a) and surrounds the functional element portion (2) in aplan view in the thickness direction (D1). In each of the plurality ofsets, the connection electrode (5; 5 a) passes through the spacer layer(41; 41 a) and the cover layer (42; 42 a) in the thickness direction(D1).

In the above-described electronic component (100; 100 a; 100 b; 100 c;100 i), moisture from the outside can be prevented from reaching the IDTelectrode (21), and the moisture resistance can be improved.

In an electronic component (100 d) according to a preferred embodiment,in each of the plurality of sets, the connection electrode (5 d) extendsalong an outer circumferential surface (403) of the cover portion (4 d)to the wiring layer (3) and is connected to the wiring layer (3). Theprotective film (7 d) covers the wiring layer (3).

In the above-described electronic component (100 d), the flexibility inselection of the material of the substrate (1) is higher than that whena through electrode is formed in the substrate (1).

In an electronic component (100; 100 a; 100 b; 100 c; 100 i) accordingto a preferred embodiment, the substrate (1) is a piezoelectricsubstrate.

An electronic component (100 e; 100 f; 100 g; 100 h; 100 j) according toa preferred embodiment includes a substrate (1 e; 1); a functionalelement portion (2); a wiring layer (3); a cover portion (4 e; 4 g; 4h); a connection electrode (5 e; 5 g); an electrically conductive layer(6 e; 6 f; 6 g; 6 h); a protective film (7 e; 7 f; 7 g; 7 h); a solderbump (8); and an alloy layer (9 e; 9 f; 9 g; 9 h). The functionalelement portion (2) is on a front surface (11 e; 11) side of thesubstrate (1 e; 1). The wiring layer (3) is on the front surface (11 e;11) side of the substrate (1 e; 1) and electrically connected to thefunctional element portion (2). The cover portion (4 e; 4 g; 4 h) is onthe front surface (11 e; 11) side of the substrate (le; 1) and protectsthe functional element portion (2). The connection electrode (5 e; 5 g;5 h) is on the wiring layer (3) and extends in the thickness direction(D1) of the substrate (1 e; 1). The electrically conductive layer (6 e;6 f; 6 g; 6 h) is on a back surface (12 e; 12 f; 12 g; 12 h) of thesubstrate (le; 1) that is opposite to the front surface (11 e; 11) andon the connection electrode (5 e; 5 g; 5 h) and electrically connectedto the wiring layer (3) via the connection electrode (5 e; 5 g; 5 h).The protective film (7 e; 7 f; 7 g; 7 h) covers the back surface (12 e;12) of the substrate (1 e; 1) and the electrically conductive layer (6e; 6 f; 6 g; 6 h) and has an opening (71) in a projection region of partof the electrically conductive layer (6 e; 6 f; 6 g; 6 h) in thethickness direction (D1). The solder bump (8) is electrically connectedto the electrically conductive layer (6 e; 6 f; 6 g; 6 h) via theopening (71). The alloy layer (9 e; 9 f) is formed between the solderbump (8) and the electrically conductive layer (6 e; 6 f; 6 g; 6 h) inthe thickness direction (D1) to join the solder bump (8) to theelectrically conductive layer (6 e; 6 f; 6 g; 6 h). The alloy layer (9e; 9 f) differs in at least one of composition and a combination ofelements from the solder bump (8). The electronic component (100 e; 100f; 100 g; 100 h; 100 j) includes a plurality of sets of the wiring layer(3), the connection electrode (5 e; 5 g; 5 h), the electricallyconductive layer (6 e; 6 f; 6 g; 6 h), the solder bump (8), and thealloy layer (9 e; 9 f; 9 g; 9 h). The protective film (7 e; 7 f; 7 g; 7h) has a plurality of the openings (71) corresponding to the pluralityof sets. In at least one set of the plurality of sets, the connectionelectrode (5 e; 5 g; 5 h) is disposed such that at least a portionthereof does not overlap the solder bump (8) in a plan view in thethickness direction (D1). A surface (601 e; 601 f; 601 g; 601 h) of theelectrically conductive layer (6 e; 6 f; 6 g; 6 h) that is located on aprotective film (7 e; 7 f; 7 g; 7 h) side is in contact with theprotective film (7 e; 7 f; 7 g; 7 h) in a region between the alloy layer(9 e; 9 f; 9 g; 9 h) and an edge (602 e; 602 f; 602 g; 602 h) of theelectrically conductive layer (6 e; 6 f; 6 g; 6 h) that is located on aconnection electrode (5 e; 5 g; 5 h) side in a plan view in thethickness direction (D1).

In the above-described electronic component (100 e; 100 f; 100 g; 100 h;100 j), the moisture resistance can be improved.

In an electronic component (100 e; 100 f; 100 g; 100 h; 100 j) accordingto a preferred embodiment, in a set of the plurality of sets thatdiffers from the at least one set, the connection electrode (5) isdisposed so as to entirely or substantially entirely overlap the solderbump (8) in a plan view in the thickness direction (D1).

In an electronic component (100 e; 100 f; 100 g; 100 h; 100 j) accordingto a preferred embodiment, in the at least one set, the connectionelectrode (5 e; 5 g; 5 h) is spaced apart from the solder bump (8) in aplan view in the thickness direction (D1).

In the above-described electronic component (100 e; 100 f; 100 g; 100 h;100 j), in the connection electrode (5 e; 5 g; 5 h) in the at least oneset, the distance from the solder bump (8) to the connection electrode(5 e; 5 g; 5 h) is larger than that when the connection electrode (5 e;5 g; 5 h) includes a portion overlapping the solder bump (8) in a planview in the thickness direction (D1). Therefore, moisture from theoutside is unlikely to reach the connection electrode (5 e; 5 g; 5 h),and the moisture resistance can be improved.

In an electronic component (100 e; 100 f; 100 g; 100 h; 100 j) accordingto a preferred embodiment, in each of the plurality of sets, theelectrically conductive layer (6 e; 6 f; 6 g; 6 h) surrounds the entireor substantially the entire circumference of the alloy layer (9 e; 9 f;9 g; 9 h).

In the above-described electronic component (100 e; 100 f; 100 g; 100 h;100 j), the moisture resistance can be further improved as compared withthe case where, in each of the plurality of sets, the electricallyconductive layer (6 e; 6 f; 6 g; 6 h) does not surround the entire orsubstantially the entire circumference of the alloy layer (9 e; 9 f; 9h; 9 g).

In an electronic component (100 e; 100 f; 100 g; 100 h; 100 j) accordingto a preferred embodiment, in each of the plurality of sets, at least aportion of the alloy layer (9 e; 9 f; 9 g; 9 h) is interposed betweenthe protective film (7 e; 7 f; 7 g; 7 h) and the electrically conductivelayer (6 e; 6 f; 6 g; 6 h) in the thickness direction (D1).

In the above-described electronic component (100 e; 100 f; 100 g; 100 h;100 j), the joint strength between the solder bump (8) and theelectrically conductive layer (6 e; 6 f; 6 g; 6 h) can be improved ascompared with the case where, in each of the plurality of sets, at leasta portion of the alloy layer (9 e; 9 f; 9 g; 9 e) is not interposedbetween the protective film (7 e; 7 f; 7 g; 7 h) and the electricallyconductive layer (6 e; 6 f; 6 g; 6 h) in the thickness direction (D1) ofthe substrate (1 e; 1).

In an electronic component (100 e; 100 f; 100 g; 100 h; 100 j) accordingto a preferred embodiment, in the at least one set, the length (L6) of aportion of the electrically conductive layer (6 e; 6 f; 6 g; 6 h) thatoverlaps the protective film (7 e; 7 f; 7 g; 7 h) in the region betweenthe alloy layer (9 e; 9 f; 9 g; 9 h) and the edge (602 e; 602 f; 602 g;602 h) of the electrically conductive layer (6 e; 6 f; 6 g; 6 h) that islocated on the connection electrode (5 e; 5 g; 5 h) side in a plan viewin the thickness direction (D1) is larger than the length (L9) of aportion of the alloy layer (9 e; 9 f; 9 g; 9 h) that overlaps theprotective film (7 e; 7 f; 7 g; 7 h).

In the above-described electronic component (100 e; 100 f; 100 g; 100 h;100 j), the moisture resistance can be further improved.

In an electronic component (100 e; 100 f; 100 h; 100 j) according to apreferred embodiment, in each of the plurality of sets, the electricallyconductive layer (6 e; 6 f; 6 h) includes a Au layer (third layer 63)overlapping the protective film (7 e; 7 f; 7 h) in a plan view in thethickness direction (D1). The Au layer (third layer 63) is connected tothe alloy layer (9 e; 9 f; 9 h). The alloy layer (9 e; 9 f; 9 h)includes Au.

In the above-described electronic component (100 e; 100 f; 100 h; 100j), the weather resistance of the electrically conductive layer (6 e; 6f; 6 h) and the alloy layer (9 e; 9 f; 9 h) in each of the plurality ofsets can be improved.

In an electronic component (100 f) according to a preferred embodiment,in each of the plurality of sets, the electrically conductive layer (6f) includes a close contact layer (64). The close contact layer (64) isinterposed between the Au layer (third layer 63) and the protective film(7 f). The close contact layer (64) has higher adhesion to theprotective film (7 f) than the Au layer (third layer 63).

In the above-described electronic component (100 f), since theelectrically conductive layer (6 f) in each of the plurality of setsincludes the close contact layer (64), the adhesion between theprotective film (7 f) and the surface (601 f) of the electricallyconductive layer (6 f) that is located on the protective film (7 f) sidein the thickness direction (D1) of the substrate (1) can be improved,and the therefore moisture resistance can be further improved.

In an electronic component (100 f) according to a preferred embodiment,the protective film (7 f) includes one material selected from the groupconsisting of an epoxy resin, a polyimide resin, and an acrylic resin.The close contact layer (64) includes one material selected from thegroup consisting of Ti, Cr and NiCr.

In the above-described electronic component (100 f), the close contactlayer (64) can be formed by sputtering, vapor deposition, etc.

In an electronic component (100 g) according to a preferred embodiment,in each of the plurality of sets, the electrically conductive layer (6g) includes Cu.

In the above-described electronic component (100 g), the resistance ofthe electrically conductive layer (6 g) can be reduced.

In an electronic component (100 e; 100 f; 100 g; 100 h; 100 j) accordingto a preferred embodiment, in the at least one set, the maximum heightroughness of the surface (601 e; 601 f; 601 g; 601 h) of theelectrically conductive layer (6 e; 6 f; 6 g; 6 h) that is located onthe protective film (7 e; 7 f; 7 g; 7 h) side is larger than the maximumheight roughness of a surface (901 e; 901 f; 901 g; 901 h) of the alloylayer (9 e; 9 f; 9 g; 9 h) that is located on the protective film (7 e;7 f; 7 g; 7 h) side.

In the above-described electronic component (100 e; 100 f; 100 g; 100 h;100 j), the moisture resistance can be improved as compared with thecase where the maximum height roughness of the surface (601 e; 601 f;601 g; 601 h) of the electrically conductive layer (6 e; 6 f; 6 g; 6 h)that is located on the protective film (7 e; 7 f; 7 g; 7 h) side isequal to or lower than the maximum height roughness of the surface (901e; 901 f; 901 g; 901 h) of the alloy layer (9 e; 9 f; 9 g; 9 h) that islocated on the protective film (7 e; 7 f; 7 g; 7 h) side.

In an electronic component (100 e; 100 f; 100 g; 100 h; 100 j) accordingto a preferred embodiment, in the at least one set, the maximum heightroughness of the surface (601 e; 601 f; 601 g; 601 h) of theelectrically conductive layer (6 e; 6 f; 6 g; 6 h) that is located onthe protective film (7 e; 7 f; 7 g; 7 h) side is 1 μm or more.

In the above-described electronic component (100 e; 100 f; 100 g; 100 h;100 j), the moisture resistance can be improved as compared with thecase where the maximum height roughness of the surface (601 e; 601 f;601 g; 601 h) of the electrically conductive layer (6 e; 6 f; 6 g; 6 h)that is located on the protective film (7 e; 7 f; 7 g; 7 h) side is lessthan 1 μm.

In an electronic component (100 e; 100 f; 100 g; 100 j) according to apreferred embodiment, in each of the plurality of sets, the connectionelectrode (5 e; 5 g) is a through electrode passing through thesubstrate (1 e; 1) in the thickness direction (D1) of the substrate (1e; 1).

The above-described electronic component (100 e; 100 f; 100 g; 100 j)can be reduced in size.

In an electronic component (100 h) according to a preferred embodiment,in each of the plurality of sets, the connection electrode (5h) extendsalong an outer circumferential surface (13) of the substrate (1) to thefront surface (11) of the substrate (1) and is connected to the wiringlayer (3).

In the above-described electronic component (100 h), the flexibility inselection of the material of the substrate (1) is higher than that whena through electrode is formed in the substrate (1).

While preferred embodiments of the present invention have been describedabove, it is to be understood that variations and modifications will beapparent to those skilled in the art without departing from the scopeand spirit of the present invention. The scope of the present invention,therefore, is to be determined solely by the following claims.

What is claimed is:
 1. An electronic component comprising: a substrate;a functional element portion that is on a front surface side of thesubstrate; a wiring layer that is on the front surface side of thesubstrate and electrically connected to the functional element portion;a cover portion that is on the front surface side of the substrate andprotects the functional element portion; a connection electrode that ison the wiring layer and extends in a thickness direction of thesubstrate; an electrically conductive layer that is on the cover portionand the connection electrode and electrically connected to the wiringlayer via the connection electrode; a protective film that covers thecover portion and the electrically conductive layer and includes anopening in a projection region of a portion of the electricallyconductive layer in the thickness direction; a solder bump that iselectrically connected to the electrically conductive layer via theopening; and an alloy layer that is between the solder bump and theelectrically conductive layer in the thickness direction to join thesolder bump to the electrically conductive layer and differs in at leastone of composition and a combination of elements from the solder bump;wherein the electronic component includes a plurality of sets of thewiring layer, the connection electrode, the electrically conductivelayer, the solder bump, and the alloy layer; the protective filmincludes a plurality of the openings corresponding to the plurality ofsets; and in at least one set of the plurality of sets: the connectionelectrode is structured such that at least a portion thereof does notoverlap the solder bump in a plan view in the thickness direction; and asurface of the electrically conductive layer that is located on aprotective film side is in contact with the protective film in a regionbetween the alloy layer and an edge of the electrically conductive layerthat is located on a connection electrode side in the plan view in thethickness direction.
 2. The electronic component according to claim 1,wherein in a set of the plurality of sets that differs from the at leastone set, the connection electrode entirely or substantially entirelyoverlaps the solder bump in the plan view in the thickness direction. 3.The electronic component according to claim 1, wherein in the at leastone set, the connection electrode is spaced apart from the solder bumpin the plan view in the thickness direction.
 4. The electronic componentaccording to claim 1, wherein in each of the plurality of sets, theelectrically conductive layer surrounds an entire or substantially anentire circumference of the alloy layer.
 5. The electronic componentaccording to claim 1, wherein in each of the plurality of sets, at leasta portion of the alloy layer is interposed between the protective filmand the electrically conductive layer in the thickness direction.
 6. Theelectronic component according to claim 5, wherein in the at least oneset, a length of a portion of the electrically conductive layer thatoverlaps the protective film in the region between the alloy layer andthe edge of the electrically conductive layer that is located on theconnection electrode side in the plan view in the thickness direction islarger than a length of a portion of the alloy layer that overlaps theprotective film.
 7. The electronic component according to claim 1,wherein in each of the plurality of sets, the electrically conductivelayer includes an Au layer overlapping the protective film in the planview in the thickness direction; the Au layer is connected to the alloylayer; and the alloy layer includes Au.
 8. The electronic componentaccording to claim 7, wherein in each of the plurality of sets, theelectrically conductive layer includes a close contact layer that isinterposed between the Au layer and the protective film and has higheradhesion to the protective film than the Au layer.
 9. The electroniccomponent according to claim 8, wherein the protective film includes onematerial selected from a group consisting of an epoxy resin, a polyimideresin, and an acrylic resin; and the close contact layer includes onematerial selected from a group consisting of Ti, Cr, and NiCr.
 10. Theelectronic component according to claim 1, wherein in each of theplurality of sets, the electrically conductive layer includes Cu. 11.The electronic component according to claim 1, wherein in the at leastone set, a maximum height roughness of the surface of the electricallyconductive layer that is located on the protective film side is largerthan a maximum height roughness of a surface of the alloy layer that islocated on the protective film side.
 12. The electronic componentaccording to claim 11, wherein in the at least one set, the maximumheight roughness of the surface of the electrically conductive layerthat is located on the protective film side is about 1 μm or more. 13.The electronic component according to claim 1, wherein in each of theplurality of sets, the solder bump overlaps an entirety or substantiallyan entirety of the opening in the plan view in the thickness direction.14. The electronic component according to claim 1, wherein in each ofthe plurality of sets, the connection electrode is a through electrodepassing through the cover portion in the thickness direction of thesubstrate.
 15. The electronic component according to claim 14, whereinthe functional element portion includes an Interdigital Transducer (IDT)electrode; the substrate has piezoelectricity at least in a region inwhich the IDT electrode is provided; the cover portion includes: a coverlayer that opposes the substrate in the thickness direction and isspaced apart from the functional element portion; and a spacer layerthat has a frame shape, is interposed between the substrate and thecover layer, and surrounds the functional element portion in a plan viewin the thickness direction; and in each of the plurality of sets, thethrough electrode passes through the spacer layer and the cover layer inthickness direction.
 16. The electronic component according to claim 1,wherein in each of the plurality of sets, the connection electrodeextends along an outer circumferential surface of the cover portion tothe wiring layer and is connected to the wiring layer; and theprotective film covers the wiring layer in each of the plurality ofsets.
 17. The electronic component according to claim 15, wherein thesubstrate is a piezoelectric substrate.
 18. An electronic componentcomprising: a substrate; a functional element portion that is on a frontsurface side of the substrate; a wiring layer that is on the frontsurface side of the substrate and electrically connected to thefunctional element portion; a cover portion that is on the front surfaceside of the substrate and protects the functional element portion; aconnection electrode that is on the wiring layer and extends in athickness direction of the substrate; an electrically conductive layerthat is on the connection electrode and a back surface of the substratethat is opposite to the front surface thereof, the electricallyconductive layer being electrically connected to the wiring layer viathe connection electrode; a protective film that covers the back surfaceof the substrate and the electrically conductive layer and includes anopening in a projection region of a portion of the electricallyconductive layer in the thickness direction; a solder bump that iselectrically connected to the electrically conductive layer via theopening; and an alloy layer that is between the solder bump and theelectrically conductive layer in the thickness direction to join thesolder bump to the electrically conductive layer and differs in at leastone of composition and a combination of elements from the solder bump;wherein the electronic component includes a plurality of sets of thewiring layer, the connection electrode, the electrically conductivelayer, the solder bump, and the alloy layer; the protective filmincludes a plurality of the openings corresponding to the plurality ofsets; and in at least one set of the plurality of sets: the connectionelectrode is structured such that at least a portion thereof does notoverlap the solder bump in a plan view in the thickness direction; and asurface of the electrically conductive layer that is located on aprotective film side is in contact with the protective film in a regionbetween the alloy layer and an edge of the electrically conductive layerthat is located on a connection electrode side in the plan view in thethickness direction.
 19. The electronic component according to claim 18,wherein in a set of the plurality of sets that differs from the at leastone set, the connection electrode entirely or substantially entirelyoverlaps the solder bump in the plan view in the thickness direction.20. The electronic component according to claim 18, wherein in the atleast one set, the connection electrode is spaced apart from the solderbump in the plan view in the thickness direction.
 21. The electroniccomponent according to claim 18, wherein in each of the plurality ofsets, the electrically conductive layer surrounds an entire orsubstantially an entire circumference of the alloy layer.
 22. Theelectronic component according to claim 18, wherein in each of theplurality of sets, at least a portion of the alloy layer is interposedbetween the protective film and the electrically conductive layer in thethickness direction.
 23. The electronic component according to claim 22,wherein in the at least one set, a length of a portion of theelectrically conductive layer that overlaps the protective film in theregion between the alloy layer and the edge of the electricallyconductive layer that is located on the connection electrode side in theplan view in the thickness direction is larger than a length of aportion of the alloy layer that overlaps the protective film.
 24. Theelectronic component according to claim 18, wherein in each of theplurality of sets, the electrically conductive layer includes an Aulayer overlapping the protective film in the plan view in the thicknessdirection; the Au layer is connected to the alloy layer; and the alloylayer includes Au.
 25. The electronic component according to claim 24,wherein in each of the plurality of sets, the electrically conductivelayer includes a close contact layer that is interposed between the Aulayer and the protective film and has higher adhesion to the protectivefilm than the Au layer.
 26. The electronic component according to claim25, wherein the protective film includes one material selected from agroup consisting of an epoxy resin, a polyimide resin, and an acrylicresin; and the close contact layer includes one material selected from agroup consisting of Ti, Cr, and NiCr.
 27. The electronic componentaccording to claim 18, wherein in each of the plurality of sets, theelectrically conductive layer includes Cu.
 28. The electronic componentaccording to claim 18, wherein in the at least one set, a maximum heightroughness of the surface of the electrically conductive layer that islocated on the protective film side is larger than a maximum heightroughness of a surface of the alloy layer that is located on theprotective film side.
 29. The electronic component according to claim28, wherein in the at least one set, the maximum height roughness of thesurface of the electrically conductive layer that is located on theprotective film side is about 1 μm or more.
 30. The electronic componentaccording to claim 18, wherein in each of the plurality of sets, theconnection electrode is a through electrode passing through thesubstrate in the thickness direction of the substrate.
 31. Theelectronic component according to claim 18, wherein in each of theplurality of sets, the connection electrode extends along an outercircumferential surface of the substrate to the front surface of thesubstrate and is connected to the wiring layer.